Display apparatus

ABSTRACT

A display apparatus with a touch detection function capable of improving accuracy is provided. The display apparatus includes: a pixel array having a plurality of pixels arranged in a matrix form; and a plurality of signal wires arranged in the pixel array. Here, when an externally-detecting object is detected, a plurality of coils having areas overlapping with each other are formed of a plurality of signal wires (drive electrodes) among the plurality of signal wires, and a magnetic field generated in the plurality of respective coils are superimposed in an overlapped area by supplying a drive signal to the plurality of coils.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/170,852, filed on Oct. 25, 2018, which application is acontinuation of U.S. patent application Ser. No. 15/147,421, filed onMay 5, 2016, which application claims priority from Japanese PatentApplication No. 2015-109263 filed on May 29, 2015, the content of whichis hereby incorporated by reference.

BACKGROUND

The present application claims priority from Japanese Patent ApplicationNo. 2015-109263 filed on May 29, 2015, the content of which is herebyincorporated by reference into this application.

In recent years, a touch detection device which is so called touch panelcapable of detecting an externally-approaching object has attractedattention. A touch panel is mounted on a display apparatus such as aliquid crystal display apparatus or integrated with a liquid crystaldisplay apparatus so as to be provided as a display apparatus with atouch detection function.

As the externally-approaching object, a touch panel enabled to use, forexample, a pen is known. By enabling the touch panel to use a pen, forexample, a small area can be assigned or hand-written characters can beinput. Various techniques to detect the touch by a pen are known. As oneof the various techniques, an electromagnetic induction system is known.In the electromagnetic induction system, high accuracy and highhandwriting pressure detection accuracy can be achieved, and a hoveringdetection function in a state in which an externally-approaching objectis separated from the touch panel surface can be also achieved, andtherefore, the system is a leading technique as the technique to detectthe touch by a pen. The touch detection technique using theelectromagnetic induction system is described in, for example, JapanesePatent Application Laid-Open Publication No. H10-49301 (Patent Document1), Japanese Patent Application Laid-Open Publication No. 2005-352572(Patent Document 2), and Japanese Patent Application Laid-OpenPublication No. 2006-163745 (Patent Document 3).

SUMMARY

As the electromagnetic induction system, a system in which a coil and abattery are mounted on a pen so as to generate a magnetic field in thepen and in which magnetic field energy is detected on a touch panel isknown. In this case, the touch panel needs a sensor plate to receive themagnetic field energy. Also, a system is known, the system in which acoil and a capacitative element are mounted on a pen so as to generate amagnetic field in a touch panel and in which the magnetic field energyis charged in the capacitative element mounted on the pen and isdetected on the touch panel. This system needs a sensor plate whichgenerates the magnetic field in the touch panel and by which themagnetic field energy from the pen is received.

In both of these electromagnetic induction systems, it is required toadd the sensor plate in order to achieve the display apparatus with thetouch detection function, leading to increase in a price (productioncost).

The present inventor has studied integration of the sensor plate and thedisplay apparatus in order to suppress the increase in the price. Thesensor plate includes a plurality of coils in order to detect and/orgenerate the magnetic field. When the display apparatus with the touchdetection function is provided by mounting the sensor plate on thedisplay apparatus, the coil can be formed of, for example, a normalmetallic wire. On the other hand, when the coil is formed of a signalwire in the display apparatus for the integration, a sheet resistance ofthe signal wire forming the coil is, for example, about one or twodigits higher than a sheet resistance of the normal metallic wire. Thus,a current flowing through the coil becomes small, and the generatedmagnetic field energy becomes small, and therefore, there is a concernabout decrease in the accuracy of the touch detection.

The Patent Documents 1 to 3 describe the touch detection device usingthe electromagnetic induction system. However, a technique inconsideration of the sheet resistance of the signal wire in the displayapparatus is neither described nor recognized therein.

An object of the present invention is to provide a display apparatuswith a touch detection function capable of improving accuracy.

A display apparatus according to an aspect of the present inventionincludes a pixel array having a plurality of pixels arranged in a matrixform and a plurality of signal wires arranged in the pixel array. Here,when the externally-approaching object is detected, a plurality of coilshaving areas overlapping with each other are formed of a plurality ofsignal wires of the plurality of signal wires, and a driving signal issupplied to the plurality of coils, so that the magnetic fieldsgenerated in the plurality of respective coils are superimposed in theoverlapped area.

The magnetic fields are superimposed in an area where the coils overlapeach other, and thus, the magnetic fields can be enhanced. Thus, even ifthe inductance of each coil is decreased by reducing the number ofwindings around each coil, the magnetic field can be enhanced in theoverlapped area. Meanwhile, by reducing the number of windings aroundthe coil, a length of a signal wire to be a coil winding wire can beshortened, so that the impedance of the coil can be decreased.Accordingly, a value of a current flowing through the coil can beincreased, so that the magnetic field generated in the overlapped areacan be enhanced. Because the generated magnetic field can be enhanced,the accuracy of the touch detection can be improved.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory diagram showing a relation between a pen and anelectronic device having a liquid crystal display apparatus with a touchdetection function;

FIGS. 2A and 2B is an explanatory diagram showing a principle of anelectromagnetic induction system;

FIGS. 3A and 3B is a waveform diagram showing the principle of theelectromagnetic induction system;

FIG. 4 is a cross-sectional view showing the cross section of a liquidcrystal display apparatus;

FIGS. 5A and 5B are a plan view and a cross-sectional view schematicallyshowing a configuration of a liquid crystal display apparatus accordingto a first embodiment, respectively;

FIG. 6 is a block diagram showing a configuration of the liquid crystaldisplay apparatus according to the first embodiment;

FIG. 7 is a plan view showing a configuration of a module mounted withthe liquid crystal display apparatus according to the first embodiment;

FIG. 8 is a plan view showing a configuration of a display panel of theliquid crystal display apparatus according to the first embodiment;

FIG. 9 is a cross-sectional view showing the cross section of the liquidcrystal display apparatus according to the first embodiment;

FIG. 10 is a circuit diagram showing the configuration of the displaypanel of the liquid crystal display apparatus according to the firstembodiment;

FIG. 11 is a block diagram showing the configuration of the liquidcrystal display apparatus according to the first embodiment;

FIG. 12 is a block diagram showing an operation of touch detection ofthe liquid crystal display apparatus according to the first embodiment;

FIG. 13 is a block diagram showing an operation of touch detection ofthe liquid crystal display apparatus according to the first embodiment;

FIG. 14 is a block diagram showing an operation of touch detection ofthe liquid crystal display apparatus according to the first embodiment;

FIG. 15 is a plan view schematically showing a configuration of a coilformed in the liquid crystal display apparatus according to the firstembodiment;

FIG. 16 is a block diagram showing a configuration of a selectivecontrol circuit and a switching circuit of the liquid crystal displayapparatus according to the first embodiment;

FIG. 17 is a block diagram showing a configuration of a switchingadjustment circuit of the liquid crystal display apparatus according tothe first embodiment;

FIG. 18 is a plan view schematically showing a configuration of a coilformed in the liquid crystal display apparatus according to the firstembodiment;

FIG. 19 is a cross-sectional view schematically showing theconfiguration of the liquid crystal display apparatus according to thefirst embodiment;

FIG. 20 is a plan view schematically showing the configuration of theliquid crystal display apparatus according to the first embodiment;

FIG. 21 is a cross-sectional view schematically showing theconfiguration of the liquid crystal display apparatus according to thefirst embodiment;

FIG. 22 is a plan view schematically showing the configuration of theliquid crystal display apparatus according to the first embodiment;

FIG. 23 is a block diagram showing a configuration of a liquid crystaldisplay apparatus according to the second embodiment;

FIG. 24 is a block diagram showing a configuration of a liquid crystaldisplay apparatus according to the second embodiment;

FIG. 25 is a block diagram showing an operation of touch detection ofthe liquid crystal display apparatus according to the second embodiment;

FIG. 26 is a block diagram showing an operation of touch detection ofthe liquid crystal display apparatus according to the second embodiment;

FIG. 27 is a block diagram showing an operation of touch detection ofthe liquid crystal display apparatus according to the second embodiment;

FIG. 28 is a block diagram showing an operation of touch detection ofthe liquid crystal display apparatus according to the second embodiment;

FIG. 29 is a block diagram showing a configuration of a liquid crystaldisplay apparatus according to the third embodiment;

FIG. 30A is a waveform diagram showing an operation of a liquid crystaldisplay apparatus according to the fourth embodiment;

FIG. 30B is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fourth embodiment;

FIG. 30C is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fourth embodiment;

FIG. 30D is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fourth embodiment;

FIG. 30E is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fourth embodiment;

FIG. 30F is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fourth embodiment;

FIG. 30G is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fourth embodiment;

FIG. 31 is a block diagram showing a configuration of a liquid crystaldisplay apparatus according to the fifth embodiment;

FIG. 32A is a waveform diagram showing an operation of a liquid crystaldisplay apparatus according to the fifth embodiment;

FIG. 32B is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fifth embodiment;

FIG. 32C is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fifth embodiment;

FIG. 32D is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fifth embodiment;

FIG. 32E is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fifth embodiment;

FIG. 32F is a waveform diagram showing an operation of the liquidcrystal display apparatus according to the fifth embodiment;

FIG. 33 is a schematic diagram showing an outline of a liquid crystaldisplay apparatus according to the third embodiment;

FIG. 34 is a block diagram showing a configuration of a liquid crystaldisplay apparatus studied by the present inventors;

FIG. 35 is a block diagram showing a configuration of the liquid crystaldisplay apparatus studied by the present inventors; and

FIG. 36 is a block diagram showing a configuration of the liquid crystaldisplay apparatus studied by the present inventors.

DETAILED DESCRIPTION

Embodiments of the present application will be described below in detailwith reference to the drawings.

The following is explanation for each embodiment of the presentinvention with reference to drawings. Note that disclosure is merely oneexample, and appropriate change with keeping the concept of the presentinvention which can be easily thought up by those who skilled in the artis obviously contained in the scope of the present invention. Also, inorder to make the clear description, the drawings are illustrated moreschematically for a width, a thickness, a shape, and others of eachportion than those in an actual aspect in some cases. However, they aremerely examples, and do not restrict the interpretation of the presentinvention.

In the present specification and each drawing, similar elements to thosedescribed earlier for the already-described drawings are denoted by thesame reference characters, and detailed description for them isappropriately omitted in some cases.

The following is the explanation of a liquid crystal display apparatuswith a touch detection function as a display apparatus with a touchdetection function. However, the present invention is not limited tosuch an example and can also be applied to an OLED display apparatuswith a touch detection function. While two methods have been describedas examples of the electromagnetic induction system, a case ofapplication of the latter method will be described here. In the lattermethod, there is no need to mount a battery on a pen, and thus, the pencan be downsized, and/or, the flexibility of a shape of the pen can beimproved.

First Embodiment

<Basic Principle of the Electromagnetic Induction System>

First, the basic principle of the electromagnetic induction system willbe described. FIG. 1 is an explanatory diagram schematically showing therelation between a pen and an electronic device having a liquid crystaldisplay apparatus with a touch detection function. FIGS. 2 and 3 areexplanatory diagrams each schematically showing the basic principle ofthe electromagnetic induction system.

In FIG. 1, the electronic device includes a liquid crystal displayapparatus 1 housed in a metallic cover, a light guiding plate, a sensorplate, and a magnetic sheet. In the example shown in this drawing, thesensor plate is mounted between the liquid crystal display apparatus 1and the metallic cover. While the sensor plate is provided with aplurality of coils, FIG. 1 schematically shows one of these coils as asensor plate internal coil (hereinafter, also simply called a coil) L2.

A coil and a capacitative element are embedded in the pen correspondingto an externally-approaching object. Although the capacitative elementis omitted, FIG. 1 schematically shows the coil embedded in the pen as apen internal coil (hereinafter, may also simply called a coil) L1. Thecoil L1 and the coil L2 are coupled to each other by a magnetic field.

Note that a TFT glass substrate, a color filter, and a CF glasssubstrate included in the liquid crystal display apparatus 1 are shownin FIG. 1 in order to schematically show the structure of the liquidcrystal display apparatus 1. A TFT substrate is formed so as to includethe TFT glass substrate and TFT not shown, and a color filter substrateis formed so as to include the CF glass substrate and the color filter.A liquid crystal layer not shown is sandwiched between the TFT substrateand the color filter substrate. The light guiding plate is fixed by afixing portion so as to be sandwiched between the liquid crystal displayapparatus 1 and the sensor plate.

The pen approaches (including contact with) the electronic device, sothat the coil L1 approaches the coil L2. Accordingly, magnetic couplingbetween the coil L1 and the coil L2 occurs, and the approach of the penis detected.

The detection will be described with reference to FIGS. 2 and 3. FIG. 2Ashows a state in which the coil L2 generates a magnetic field and FIG.2B shows a state in which the coil L1 generates a magnetic field.

In FIG. 2, the coil L2 and a pen internal capacitative element(hereinafter, may also simply called a capacitative element) “C” areconnected in parallel to each other to configure a resonance circuit. Asingle-winding coil is shown as an example of the coil L1 and has a pairof terminals. When a touch is detected (in the touch detection), oneterminal PT of the coil L1 is connected to output of a transmittingamplifier AP1 for a predetermined time, and, after the predeterminedtime, is connected to input of a receiving amplifier AP2 for apredetermined time. The other terminal of the sensor plate internal coilL1 is connected to a ground voltage Vss in touch detection.

FIG. 3 is a waveform chart showing the operation in touch detection. Thehorizontal axis of FIG. 3 represents the time, FIG. 3A shows a waveformof the output of the transmitting amplifier AP1, and FIG. 3B shows awaveform of the output of the receiving amplifier AP2.

When one terminal PT of the coil L2 is connected to the output of thetransmitting amplifier AP1, a transmission signal IN changingperiodically is supplied to the input of the transmitting amplifier AP1.Accordingly, the transmitting amplifier AP1 supplies a drive signal □1changing periodically in accordance with changes of the transmissionsignal IN to one terminal of the coil L2 for a predetermined time(magnetic field generation period) TGT as shown in FIG. 3A. Accordingly,the coil L2 generates a magnetic field. The line of magnetic force atthis time is shown as □G in FIG. 2A.

The line of magnetic force □G is generated so as to center the windingwire of the coil L2, and thus, the magnetic field on the inner side ofthe coil L2 is enhanced. When the coil L1 approaches the coil L2 and acenter axis L0 of the coil L1 is inside the coil L2 as shown in, forexample, FIG. 2A, the line of magnetic force of the coil L2 reaches thecoil L1. That is, the coil L1 is arranged inside a magnetic fieldgenerated in the coil L2, so that the coil L1 and the coil L2 aremagnetically coupled. The coil L2 generates a magnetic field changingperiodically in accordance with changes of the drive signal □1. Thus, aninduced voltage is generated in the coil L1 by the action of mutualinduction between the coil L1 and the coil L2. The capacitative elementC is charged by the induced voltage generated by the coil L1.

After the predetermined time, the one terminal PT of the coil L2 isconnected to the input of the receiving amplifier AP2 for apredetermined time (a magnetic field detection period or a currentdetection period) TDT. In the magnetic field detection period TDT, ifthe capacitative element C has been charged in the previous magneticfield generation period TGT, the coil L1 generates a magnetic field bythe charge charged in the capacitative element C. FIG. 2B shows the lineof magnetic force of the coil L1 generated by the charge charged in thecapacitative element C as □D.

If the pen internal coil L1 approaches the sensor plate internal coil L2in the touch detection, that is, in the magnetic field generation periodTGT and the magnetic field detection period TDT, the capacitativeelement C is charged in the magnetic field generation period TGT, andthe line of magnetic force □D of the coil L1 reaches the coil L2 in themagnetic field detection period TDT. The resonance circuit is configuredby the coil L1 and the capacitative element C, and thus, a magneticfield generated by the coil L1 changes in accordance with the timeconstant of the resonance circuit. By the changes of the magnetic fieldgenerated by the coil L1, an induced voltage is generated in the coilL2. By the induced voltage, a signal changes at the one terminal PT ofthe coil L2. The change of the signal is input into the receivingamplifier AP2 as a detection signal □2 in the magnetic field detectionperiod TDT, is amplified, and is output as a sensor signal OUT from thereceiving amplifier AP2.

On the other hand, if the pen internal coil L1 does not approach thesensor plate internal coil L2 in touch detection, the capacitativeelement C is not charged or the amount of charge to be charged decreasesin the magnetic field generation period TGT. As a result, the line ofmagnetic force □D of the magnetic field generated by the coil L1 doesnot reach the coil L2 in the magnetic field detection period TDT. Thus,the detection signal □2 at the one terminal PT of the coil L2 does notchange in the magnetic field detection period TDT.

FIG. 3 shows both of a state in which the pen internal coil L1approaches the sensor plate internal coil L2 and a state in which thepen internal coil L1 does not approach the sensor plate internal coilL2. That is, the state in which the pen internal coil L1 does notapproach the sensor plate internal coil L2 is shown on the left side ofFIG. 3, and the state in which the pen internal coil L1 approaches thesensor plate internal coil L2 is shown on the right side thereof. Thus,in FIG. 3B, the detection signal □2 does not change in the magneticfield detection period TDT shown on the left side, and the detectionsignal □2 changes in the magnetic field detection period TDT shown onthe right side. The touch by the pen can be detected by determining thecase of change of the detection signal □2 to be a case with the pen, anddetermining the case of no change of the detection signal □2 to be acase without the pen.

While FIG. 3 shows the determinations of the cases with and without thepen, the value of the detection signal □2 changes depending on thedistance between the coil L1 and the coil L2, and thus, the distancebetween the pen and the sensor plate or a pen pressure of the pen can bealso determined.

<Integrated Structure of the Liquid Crystal Display Apparatus and theSensor Plate>

The present inventors have considered that, if the liquid crystaldisplay apparatus 1 and the sensor plate are prepared separately asshown in FIG. 1, an electronic device becomes expensive because thesensor plate is expensive. Thus, the present inventors have consideredforming the sensor plate by a layer of the liquid crystal displayapparatus 1 to integrate the liquid crystal display apparatus and thesensor plate. FIG. 4 is a cross-sectional view showing a schematic crosssection of the liquid crystal display apparatus 1 in which the sensorplate is integrated as a sensor layer. FIG. 4 is similar to FIG. 1, andthus, differences will mainly be described. In FIG. 1, a sensor plate isprepared separately from the liquid crystal display apparatus 1 so thatthe sensor plate is provided between a light guiding plate and amagnetic sheet. In FIG. 4, by contrast, a sensor layer is formed on aTFT glass substrate. Accordingly, the sensor layer corresponding to asensor plate is provided in the liquid crystal display apparatus 1, andthus, increase in a price can be suppressed.

FIG. 5 is a diagram schematically showing the structure of the liquidcrystal display apparatus 1, FIG. 5A schematically shows a plane of theliquid crystal display apparatus 1, and FIG. 5B schematically shows across section of the liquid crystal display apparatus 1. In FIGS. 5A and5B, TL(0) to TL(P) indicate drive electrodes formed on a TFT glasssubstrate. In FIG. 5A, the drive electrodes TL(0) to TL(p) extend in ahorizontal direction (row direction) and are arranged in parallel in avertical direction (column direction). That is, each of the driveelectrodes TL(0) to TL(p) is formed so as to be parallel to each otherin an extending direction. As shown in FIG. 5B, a liquid crystal layeris provided on an upper side of the drive electrodes TL(0) to TL(P), anda color filter and a CF glass substrate are further formed on an upperside of the liquid crystal layer. In addition, a light polarizing plateis formed on an upper side of the CF glass substrate. In FIG. 5, a caseof view from above is described as the term “upper side” as shown inFIG. 5B in order to make the description easier. However, of course, the“upper side” changes to a “lower side” or a “lateral side” depending onthe direction of the visual view.

To each of the drive electrodes TL(0) to TL(p), a drive signal fordisplay (display drive signal) is supplied in display. Thus, when onlythe display is considered, the drive electrodes TL(0) to TL(P) may beelectrically connected to each other. In other words, the driveelectrodes TL(0) to TL(p) may be one drive electrode. In the firstembodiment, however, a drive electrode is used as a coil winding wire inthe touch detection. Thus, in the first embodiment, the drive electrodesTL(0) to TL(p) are electrically separated from each other. For example,a common display drive signal is supplied to the mutually separateddrive electrodes TL(0) to TL(p) in display, and predetermined driveelectrodes are electrically connected to each other to form a coil intouch detection.

That is, in the first embodiment, a layer of signal wires forming thedrive electrodes TL(0) to TL(P) is used as a sensor layer. A displaydrive signal is supplied to the drive electrodes TL(0) to TL(p) indisplay. Therefore, the drive electrodes TL(0) to TL(p) are used incommon in display and in touch detection (used for both of display andtouch detection). Thus, in the first embodiment, there is no need to adda layer to form a coil winding wire, and besides, the increase in theprice can be suppressed. Because the drive electrodes TL(0) to TL(p)also function as a common electrode for display, note that each of thedrive electrodes TL(0) to TL(p) can be regarded as a common electrode.Thus, in this specification, the drive electrodes TL(0) to TL(p) mayalso be called common electrodes.

<Study by the Present Inventors>

Next, problems caused when a coil is formed by using signal wires insidethe liquid crystal display apparatus 1 such as the drive electrodesTL(0) to TL(p) will be described based on results of the study by thepresent inventors. FIGS. 34 to 36 are block diagrams each showing theconfiguration of the liquid crystal display apparatus 1 studied by thepresent inventors. These diagrams show states in touch detection.

In FIG. 34, TL(n−3) to TL(n+13) indicate drive electrodes. In thisdrawing, VL01 indicates a voltage wire, and a display drive signal issupplied to the drive electrodes TL(n−3) to TL(n+13) via the voltagewire VL01 in display. Also in FIG. 34, VL02 indicates a voltage wire,and, for example, the ground voltage Vss is supplied to the voltage wireVL02 in touch detection. Further in FIG. 34, LL01 indicates a signalwire, and a coil clock signal whose voltage changes periodically issupplied to the signal wire LL01 in touch detection.

In FIG. 34, LL11, LL12, LL21, LL22, LL31, LL32, LL40, LL50, and LL60indicate signal wires, and x00 to x16 and y00 to y16 indicate switches.Each of the switches x00 to x16 and y00 to y16 includes a commonterminal “c” and three terminals (a first terminal “p1”, a secondterminal “p2”, and a third terminal). In order to avoid complexity ofthe drawing, the third terminal is omitted in FIG. 34. The thirdterminal of each of the switches x00 to x16 and y00 to y16 is connectedto no signal wire, and is in a floating state. The first terminal p1 ofeach of the switches x00 to x16 is connected to the voltage wire VL01,and the second terminals p2 thereof are connected to the signal wiresLL11, LL12, LL21, LL22, LL32, LL32, respectively. The first terminal p1of each of the switches y00 to y16 is connected to the voltage wireVL01, and the second terminals p2 thereof are connected to thecorresponding signal wires LL40, LL50, LL60, the voltage wire VL02, andthe signal wire LL01, respectively. In each of these switches x00 to x16and y00 to y16, the common terminal “c” is selectively connected to thefirst terminal p1, the second terminal p2, or the third terminal basedon a switch control signal not shown.

First, in explanation of a case of display, the switches x00 to x16 andy00 to y16 are controlled based on a switch control signal such that thecommon terminal “c” of each of them is connected to the first terminalp1. Accordingly, the end of each of the drive electrodes TL(n−3) toTL(n+13) is connected to the voltage wire VL01 via the switches x00 tox16 and y00 to y16. As a result, the desired display drive signal issupplied to the end of each of the drive electrodes TL(n−3) to TL(n+13)via the voltage wire VL01 in display, so that a desired display ispossible.

A switch connected to a drive electrode functioned as a coil windingwire among the switches x00 to x16 and y00 to y16 is controlled so thatthe common terminal “c” is connected to the second terminal p2 in touchdetection, and a switch connected to a drive electrode not functioned asthe coil winding wire is controlled so that the common terminal c isconnected to the third terminal. As explained in FIG. 2, the magneticfield is enhanced inside the coil. Thus, the switches x00 to x16 and y00to y16 are controlled so that drive electrodes arranged to sandwich anarea that generates a magnetic field therebetween configure a coilwinding wire.

FIG. 34 shows a case in which an area corresponding to drive electrodesTL(n) to TL(n+3) is assigned as an area where a strong magnetic field isgenerated. Thus, the switches x01, x02, x07, and x08 and the switchesy01, y02, y07, and y08 are selected so that the drive electrodesTL(n−2), TL(n−1), TL(n+4), and TL(n+5) arranged so as to sandwich thesedrive electrodes TL(n) to TL(n+3) become a coil winding wire. In theselected switches x01, x02, x07, x08, y01, y02, y07, y08, the commonterminal c is connected to the second terminal p2. On the other hand, ineach of switches that are not selected, the common terminal c isconnected to the third terminal.

The third terminal is in a floating state. Therefore, even if the commonterminal c is connected to the third terminal, the third terminal is ina high-impedance state. Thus, FIG. 34 shows the common terminal c of theswitch not selected to be in a floating state. If, for example, theswitches x00, y00 are exemplified, these switches are not selected, andthus, the common terminal c is connected no signal wire and is shown asin a floating state in FIG. 34.

In the switches x01 and x07, the common terminal c is connected to thesecond terminal p2, so that one end of the drive electrode TL(n−2) isconnected to the signal wire L11 via the switch x01, and the signal wireL11 is connected to one end of the drive electrode TL(n+4) via theswitch x07. Similarly in the switches x02 and x08, the common terminal cis connected to the second terminal p2, so that one end of the driveelectrode TL(n−1) is connected to the signal wire L12 via the switchx02, and the signal wire L12 is connected to one end of the driveelectrode TL(n+5) via the switch x08.

In the switches y02 and y07, the common terminal c is connected to thesecond terminal p2, so that the other end of the drive electrode TL(n−1)is connected to the signal wire LL40 via the switch y02, and the signalwire LL40 is connected to the other end of the drive electrode TL(n+4)via the switch y07. Further in the switch y01, the common terminal c isconnected to the second terminal p2, so that the other end of the driveelectrode TL(n−2) is connected to the voltage wire VL02 via the switchy01. Also in the switch y08, the common terminal c is connected to thesecond terminal p2, so that the other end of the drive electrode TL(n+5)is connected to the signal wire LL01 via the switch y08.

Accordingly, the drive electrodes TL(n−2), TL(n−1), TL(n+4), TL(n+5) andthe signal wires LL11, LL12, LL40 are connected in series between thesignal wire LL01 and the voltage wire VL02. In this case, the driveelectrodes TL(n−2), TL(n−1), TL(n+4), TL(n+5) are arranged in parallelwith each other, and thus, function as a coil winding wire. By supplyingthe ground voltage Vss to the voltage wire VL02 and supplying a coilclock signal whose voltage changes periodically to the signal wire LL01,voltages are supplied to both ends of the coil so that, for example, acurrent shown as an arrow I(n) in FIG. 34 flows. Accordingly, a magneticfield is generated by a coil having the drive electrodes TL(n−2),TL(n−1), TL(n+4), TL(n+5) as a winding wire.

If a pen approaches an area (corresponding to the drive electrodes TL(n)to TL(n+3)) inside the coil, the pen internal capacitative element C ischarged in the magnetic field generation period TGT. In the magneticfield detection period TDT, an induced voltage is generated in the coilhaving the drive electrodes TL(n−2), TL(n−1), TL(n+4), TL(n+5) as thewinding wire by a magnetic field generated by the pen internal coil, sothat a signal in the signal wire LL01 changes. The change is detected asa detection signal. On the other hand, if the pen does not approach thearea, the capacitative element C is not charged in the magnetic fieldgeneration period TGT. As a result, in the magnetic field detectionperiod TDT, the signal in the signal wire LL01 does not change.Therefore, the touch by the pen can be detected by determining thesignal change in the signal wire LL01.

FIG. 35 shows a state in which, after it is detected whether or not thepen has approached the area inside the coil (corresponding to the driveelectrodes TL(n) to TL(n+3)) described with reference to FIG. 34, it isdetected whether or not the pen approaches a close area.

The configuration shown in FIG. 35 is the same as the configuration inFIG. 34. The difference from FIG. 34 is that the area inside the coil,that is, the area where a magnetic field is generated is different. Thatis, the switches x00 to x16 and y00 to y16 are controlled so that amagnetic field is generated in an area (drive electrodes TL(n+4) toTL(n+7)) close to the area (drive electrodes TL(n) to TL(n+3)). Inexplanation with reference to FIG. 35, the switches x05, x06, x11, x12and the switches y05, y06, y11, and y12 connected to the driveelectrodes TL(n+2), TL(n+3), TL(n+8), TL(n+9) arranged so as to sandwichthe drive electrodes TL(n+4) to TL(n+7) are controlled to be selected sothat the common terminal c in these selected switches is connected tothe second terminal p2.

On the other hand, remaining non-selected switches are controlled sothat the common terminal c is connected to the third terminal.Accordingly, in the touch detection, the drive electrodes TL(n+2),TL(n+3), TL(n+8), TL(n+9) and the signal wires LL21, LL22, LL50 areconnected in series between the signal wire LL01 and the voltage wireVL02 via the selected switches x05, x06, x11, x12 and y05, y06, y11, andy12. That is, a coil having the drive electrodes TL(n+2), TL(n+3),TL(n+8), TL(n+9) as a winding wire is formed.

As similar to the description with reference to FIG. 34, by supplying acoil clock signal to the coil having the drive electrodes TL(n+2),TL(n+3), TL(n+8), TL(n+9) as a winding wire via the signal wire LL01 andsupplying the ground voltage Vss to the voltage wire VL02, a magneticfield is generated in the area inside the coil (corresponding to thedrive electrodes TL(n+4) to TL(n+7)). By detecting a signal change inthe signal wire LL01 in the magnetic field detection period TDT afterthe magnetic field is generated, it can be detected whether or not a penapproaches the area inside the coil (corresponding to the driveelectrodes TL(n+4) to TL(n+7)). Note that FIG. 35 shows a currentflowing through the coil in the magnetic field generation period TGT asan arrow “I(n+4)”.

FIG. 36 shows a state in which, after it is detected whether or not thepen has approached the area inside the coil (corresponding to the driveelectrodes TL(n+4) to TL(n+7)) described with reference to FIG. 35, itis detected whether or not the pen approaches a close area.

The configuration shown in FIG. 36 is also the same as the configurationin FIG. 35. The difference from FIG. 35 is that the area inside thecoil, that is, the area where a magnetic field is generated isdifferent. That is, the switches x00 to x16 and y00 to y16 arecontrolled so that a magnetic field is generated in an area (driveelectrodes TL(n+8) to TL(n+11)) close to the area (drive electrodesTL(n+4) to TL(n+7)). In the description with reference to FIG. 36,control is exercised such that the switches x09, x10, x15, x16 and theswitches y09, y10, y15, and y16 connected to the drive electrodesTL(n+6), TL(n+7), TL(n+12), TL(n+13) arranged so as to sandwich thedrive electrodes TL(n+8) to TL(n+11) are controlled to be selected sothat the common terminal c in these selected switches is connected tothe second terminal p2.

On the other hand, remaining non-selected switches are controlled sothat the common terminal c is connected to the third terminal.Accordingly, in the touch detection, the drive electrodes TL(n+6),TL(n+7), TL(n+12), TL(n+13) and the signal wires LL31, LL32, LL60 areconnected in series between the signal wire LL01 and the voltage wireVL02 via the selected switches x09, x10, x15, x16 and y09, y10, y15, andy16. That is, a coil having the drive electrodes TL(n+6), TL(n+7),TL(n+12), TL(n+13) as a winding wire is formed.

As similar to the description with reference to FIG. 34, by supplying acoil clock signal to the coil having the drive electrodes TL(n+6),TL(n+7), TL(n+12), TL(n+13) as a winding wire via the signal wire LL01and supplying the ground voltage Vss to the voltage wire VL02, amagnetic field is generated in the area inside the coil (correspondingto the drive electrodes TL(n+8) to TL(n+11)). By detecting a signalchange in the signal wire LL01 in the subsequent magnetic fielddetection period TDT, it can be detected whether or not a pen approachesthe area inside the coil (corresponding to the drive electrodes TL(n+8)to TL(n+11)). Note that FIG. 36 shows a current flowing through the coilin the magnetic field generation period TGT as an arrow I(n+8).

As described with reference to FIGS. 34 to 36, a coil can be formed intouch detection by using the drive electrodes TL(0) to TL(p). FIGS. 34to 36 show a case in which the number of windings of the formed coil istwo as an example. However, by further increasing the number ofwindings, the inductance of coil can be increased more, so that thegenerated magnetic field can be more enhanced. However, the driveelectrode is formed of, for example, a transparent electrode. The sheetresistance of a transparent electrode is much larger than that of aregular metallic wire. Thus, if the number of windings of coil isincreased, the impedance of the coil, that is, the impedance of the coilconnected between the signal wire LL01 and the voltage wire VL02increases, and therefore, a current flowing through the coil becomessmall. If the current flowing through the coil is small in the magneticfield generation period TGT, the generated magnetic field becomes weak.As a result, degradation of the accuracy of detection is concerned.

Note that it can be considered that the sheet resistance of the driveelectrode is decreased by electrically connecting a plurality ofauxiliary electrodes (second electrodes) having a lower sheet resistancethan the transparent electrode (first electrode) to the transparentelectrode. However, even in such a case, the sheet resistance of thedrive electrode formed of the first electrode and the plurality ofsecond electrodes is still higher than that of a regular metallic wire,and therefore, it is difficult to generate a strong magnetic field.

By the above-described study of the present inventors, it has beenunderstood that a coil can be formed in touch detection by using signalwires (drive electrodes) provided in the liquid crystal displayapparatus 1. However, because a signal wire formed of a transparentelectrode such as a transparent electrode has a high sheet resistance,the present inventors have reached such a problem that the ignorablecoil impedance in a general metallic wire cannot be ignored if the coilinductance is enhanced to be able to generate a strong magnetic field.

<Overview of the Liquid Crystal Display Apparatus>

FIG. 6 is a block diagram showing the configuration of the liquidcrystal display apparatus 1 according to the first embodiment. In FIG.6, the liquid crystal display apparatus 1 includes a display panel(liquid crystal panel) 2, a display control device 4, a gate driver 5,and a touch control device 6. The liquid crystal display apparatus 1also includes selection control circuits SR-L, SR-R, SRX-D, a switchingcircuit DSC, a selection drive circuit SDC, and switching adjustmentcircuits SCX-U, SCX-D. Since these devices and circuits included in theliquid crystal display apparatus 1 will be described in detail later, anoverview thereof will be described here.

The display panel 2 has a pixel array LCD described later with referenceto FIG. 10 in which a plurality of pixels are arranged in a matrix form.In the pixel array LCD, a plurality of signal lines, a plurality ofdrive electrodes, and a plurality of scanning lines are arranged. Here,the signal line is arranged in each column of the pixel array LCD, thedrive electrode is arranged in a row of the pixel array LCD, and theplurality of scanning lines are arranged in each row of the pixel arrayLCD. That is, in this drawing, the signal wires extend in a verticaldirection (column direction) and are arranged in parallel in ahorizontal direction (row direction). The drive electrodes extend in thehorizontal direction and are arranged in parallel in the verticaldirection. Further, the scanning lines extend in the horizontaldirection and are arranged in parallel in the vertical direction. Inthis case, a pixel is arranged in a portion where a signal line and ascanning line intersect. In a period of display (display period), pixelsare selected by signal lines and scanning lines, the voltage of thesignal line and the voltage (display drive signal) of the driveelectrode at that time are applied to the selected pixels, and theselected pixels produce a display in accordance with a voltagedifference between the signal line and the drive electrode.

The display control device 4 includes a control circuit D-CNT and asignal line driver D-DRV. The control circuit D-CNT receives a timingsignal supplied to an external terminal Tt and image informationsupplied to an input terminal Ti, forms an image signal Sn in accordancewith the image information supplied to the input terminal Ti, andsupplies the image signal Sn to the signal line driver D-DRV. The signalline driver D-DRV supplies the supplied image signal Sn to a signal lineselector 3 in a display period in a time-division mode. The controlcircuit D-CNT also receives a timing signal supplied to the externalterminal Tt and a control signal SW from the touch control device 6 toform various control signals. As the control signals formed by thecontrol circuit D-CNT, there are selection signals SEL1, SEL2 suppliedto the signal line selector 3, a synchronizing signal TSHD, a clocksignal CLK, a magnetic-field enable signal SC_EN, a display drive signalVCOMDC, control signals X-CNT, Y-CNT related to touch detection, a coilclock signal CCLK, a high-impedance control signal HZ-CT, and others.

Among signals formed by the control circuit D-CNT, the magnetic-fieldenable signal SC_EN is an enable signal indicating that touch detection(magnetic field touch detection) is performed. The synchronizing signalTSHD is a synchronizing signal that identifies a period (display period)in which the display panel 2 produces a display and a period (touchdetection period) in which touch detection is performed, and the displaydrive signal VCOMDC is a drive signal supplied to the drive electrodesin a display period.

In a display period, the signal line driver D-DRV supplies the imagesignal Sn to the signal line selector 3 in accordance with the selectionsignals SEL1, SEL2 in time-division mode. The signal line selector 3 isconnected to the plurality of signal lines arranged in the display panel2, and supplies the supplied image signal to appropriate signal lines inaccordance with the selection signals SEL1, SEL2 in a display period.The gate driver 5 forms scanning line signals Vs0 to Vsp in accordancewith a timing signal from the control circuit D-CNT in a display period,and supplies the scanning line signals Vs0 to Vsp to the scanning linesin the display panel 2. In a display period, pixels connected toscanning lines to which a high-level scanning line signal is suppliedare selected, and the display is performed when the selected pixelsperform the display in accordance with the image signal supplied to thesignal line at that time.

Although not specifically limited, the high-impedance control signalHZ-CT is supplied from the control circuit D-CNT to the signal linedriver D-DRV and the gate driver 5. The output of the signal line driverD-DRV and the gate driver 5 is put into a high-impedance state by thehigh-impedance control signal HZ-CT in a touch detection period,although not specifically limited.

The touch control device 6 includes a magnetic field detection circuitSE-DET that receives sense signals S(0) to S(p), a processing circuitPRS that extracts coordinates of the touched position by performingprocessing on a detection signal SC-D from the magnetic field detectioncircuit SE-DET, and a control circuit T-CNT. The control circuit T-CNTreceives the synchronizing signal TSHD, the clock signal CLK, and themagnetic-field enable signal SC_EN from the display control device 4,and controls the touch control device 6 so as to operate insynchronization with the display control device 4.

That is, when the synchronizing signal TSHD and the magnetic-fieldenable signal SC_EN indicate touch detection, the control circuit T-CNTperforms control so that the magnetic field detection circuit SE-DET andthe processing circuit PRS operate. The control circuit T-CNT alsoreceives a detection signal from the magnetic field detection circuitSE-DET, forms the control signal SW, and supplies the control signal SWto the control circuit D-CNT. The processing circuit PRS outputsextracted coordinates from the external terminal To as the coordinateinformation.

The display panel 2 has sides 2-U, 2-D parallel to the row of the pixelarray LCD and sides 2-R, 2-L parallel to the column of the pixel arrayLCD. Here, the side 2-U and the side 2-D are sides opposite to eachother, and the plurality of drive electrodes and the plurality ofscanning lines in the pixel array LCD are arranged so as to besandwiched therebetween. Also, the side 2-R and the side 2-L are sidesopposite to each other, and the plurality of signal lines in the pixelarray LCD are arranged so as to be sandwiched therebetween.

The switching circuit DSC is arranged along the side 2-R of the displaypanel 2, and the selection drive circuit SDC is arranged along the side2-L of the display panel 2. The switching circuit DSC is connected tothe plurality of drive electrodes arranged in the display panel 2 on theside 2-R side of the display panel 2, and the selection drive circuitSDC is connected to the plurality of drive electrodes arranged in thedisplay panel 2 on the side 2-L side of the display panel 2. That is,the switching circuit DSC and the selection drive circuit SDC areconnected to drive electrodes arranged in the display panel 2 outsidethe display panel 2.

The selection control circuit SR-R is arranged along the side 2-R of thedisplay panel 2 although not specifically limited, and the switchingcircuit DSC arranged along the same side 2-R operates in accordance withinstructions from the corresponding selection control circuit SR-R. Theselection control circuit SR-L is arranged along the side 2-L of thedisplay panel 2 although not specifically limited, and the selectiondrive circuit SDC arranged along the same side 2-L operates inaccordance with instructions from the corresponding selection controlcircuit SR-L.

The selection control circuit SR-R assigns a plurality of driveelectrodes, each of which becomes a coil winding wire, to the switchingcircuit DSC so that a plurality of coils are formed for touch detection.The switching circuit DSC electrically connects the assigned driveelectrodes, so that a plurality of coils are formed. In a displayperiod, the selection control circuit SR-R controls the switchingcircuit DSC so as to supply the display drive signal VCOMDC to driveelectrodes. The selection control circuit SR-L assigns a plurality ofdrive electrodes to be coil winding wires of a plurality of coils intouch detection for the selection drive circuit SDC. The selection drivecircuit SDC supplies a drive signal for magnetic field (magnetic-fielddrive signal) to the plurality of assigned drive electrodes. In adisplay period, the selection control circuit SR-L controls theselection drive circuit SDC so as to supply the display drive signalVCOMDC to drive electrodes.

That is, when the touch detection is instructed by the magnetic-fieldenable signal SC_EN, the selection control circuits SR-R, SR-L assign aplurality of drive electrodes arranged so as to sandwich an area wherethe touch is to be detected from the drive electrodes TL(0) to TL(p).The switching circuit DSC electrically connects the plurality ofassigned drive electrodes, and the selection drive circuit SDC suppliesa magnetic-field drive signal to the plurality of assigned driveelectrodes. As the magnetic-field drive signal at this time, theselection drive circuit SDC supplies the coil clock signal CCLK whosevoltage changes periodically. Here, the selection control circuits SR-R,SR-L assign drive electrodes so that an area where the touch is to bedetected is arranged inside a plurality of coils. That is, the selectioncontrol circuits SR-R, SR-L assign a plurality of drive electrodes fromthe drive electrodes TL(0) to TL(p) such that an area overlapped with aplurality of coils includes an area where the touch is to be detected.

Accordingly, magnetic fields generated by a plurality of coils superposein an area where the touch is to be detected in the magnetic fieldgeneration period TGT in a touch detection period, so that a strongmagnetic field is generated. In a display period, a display drive signalis supplied from both ends of the drive electrode to the driveelectrode, and thus, the voltage of the drive electrode can bestabilized.

The switching adjustment circuit SCX-U is arranged along the side 2-U ofthe display panel 2, and the switching adjustment circuit SCX-U isconnected to a plurality of signal lines arranged in the display panel 2on the side 2-U side. That is, the switching adjustment circuit SCX-U isconnected to a plurality of signal lines outside the display panel 2.The switching adjustment circuit SCX-D is connected to the plurality ofsignal lines arranged in the display panel 2 via the signal lineselector 3 arranged along the side 2-D of the display panel 2.

When the touch detection is assigned by the magnetic-field enable signalSC_EN in a touch detection period, the switching adjustment circuitsSCX-U, SCX-D electrically connect signal lines arranged in the displaypanel 2 to form a plurality of coils having signal lines as windingwires. In a touch detection period, the selection control circuit SRX-Dselects a coil formed of signal lines arranged so as to sandwich an areawhere the touch is to be detected, from the plurality of coils formed ofsignal lines. A signal change in the selected coil in the magnetic fielddetection period TDT in a touch detection period is output and suppliedto the magnetic field detection circuit SE-DET as the sense signals S(0)to S(p).

In the electromagnetic induction system described using FIGS. 2 and 3,the coil used to generate a magnetic field and the coil used to detect amagnetic field are the same as each other. However, in the firstembodiment, the coil used to generate a magnetic field and the coil usedto detect a magnetic field are different from each other. That is, amagnetic field is generated by a coil formed of drive electrodes in themagnetic field generation period TGT, and a magnetic field is detectedby a coil formed of signal lines in the magnetic field detection periodTDT. Also in this case, the basic principle of the electromagneticinduction system is the same as the basic principle described withreference to FIGS. 2 and 3. That is, in the magnetic field generationperiod TGT, the pen internal coil L1 (FIG. 2) generates an inducedvoltage based on a magnetic field generated by the coil formed of thedrive electrodes to charge the capacitative element C (FIG. 2). In themagnetic field detection period TDT, an induced voltage is generated inthe coil formed of signal lines based on a magnetic field generated bythe pen internal coil L1, and a sense signal (hereinafter, also called adetection signal) representing a signal change in the signal line or aresult of touch detection is generated.

When a coil having the signal lines as winding wires is formed by theswitching adjustment circuits SCX-U, SCX-D, the signal line selector 3electrically connects signal lines and the switching adjustment circuitSCX-D.

In a touch detection period, the magnetic field detection circuit SE-DETin the touch control device 6 is operated by the magnetic-field enablesignal SC_EN. The magnetic field detection circuit SE-DET amplifies andconverts the sense signals S(0) to S(p) into digital signals, andsupplies the digital signals to the processing circuit PRS as thedetection signal SC-D. Based on the supplied detection signal SC-D, theprocessing circuit PRS extracts coordinates of the position touched by apen and outputs the coordinates to an external terminal To as positioninformation.

For the magnetic field detection period TDT, such description that acoil is selected by the selection control circuit SRX-D has been made.However, the selection control circuit SRX-D may supply a signal changein each of coils formed of signal lines as the sense signals S(0) toS(p) to the magnetic field detection circuit SE-DET without selecting acoil. In this case, each of the sense signals S(0) to S(p) can beamplified temporally in parallel by the magnetic field detection circuitSE-DET, so that a speed of a detection operation can be increased.

An overview of operations of the switching circuit DSC, the selectiondrive circuit SDC, the switching adjustment circuits SCX-U, SCX-D, andthe selection control circuits SR-R, SR-L, SRX-D in a touch detectionperiod has been described. In a display period, they are operated asfollows.

That is, in a display period, the switching circuit DSC and theselection drive circuit SDC supply a display drive signal to a pluralityof drive electrodes. Also, the switching adjustment circuits SCX-U,SCX-D electrically isolate signal lines. Accordingly, in a displayperiod, the image signal Sn from the signal line driver D-DRV issupplied to appropriate signal lines by the signal line selector 3.Because the display drive signal is supplied to the drive electrodes,the scanning line is set to a high level and thus, a voltage differencebetween an image signal supplied to the signal line and the displaydrive signal supplied to the drive electrode is applied to the selectedpixels, so that a display in accordance with the image signal isproduced.

In the first embodiment, the drive electrode serves as a coil windingwire that generates a magnetic field and also as a signal wire thattransfers a display drive electrode. Also, the signal line serves as acoil winding wire that detects a magnetic field and also as a signalwire that transfers an image signal. Accordingly, the liquid crystaldisplay apparatus 1 with a touch detection function can be providedwhile suppressing the increase in the manufacturing cost.

In the first embodiment, a display drive signal or a magnetic-fielddrive signal is supplied to the drive electrode by the switching circuitDSC, the selection drive circuit SDC, and the selection control circuitsSR-R, SR-L. Thus, an electrode drive circuit can be considered to beconfigured of the switching circuit DSC, the selection drive circuitSDC, and the selection control circuits SR-R, SR-L.

Similarly, an image signal or a sense signal is transferred by theswitching adjustment circuits SCX-U, SCX-D and the selection controlcircuit SRX-D. Thus, a signal line drive circuit can be considered to beconfigured of the switching adjustment circuits SCX-U, SCX-D and theselection control circuit SRX-D. In this case, the signal line drivecircuit can be considered to be configured of a switching circuitincluding a first switching circuit SCX-U arranged along the side 2-U ofthe display panel 2 and second switching circuit SCX-D arranged alongthe side 2-D side of the display panel 2 and the selection controlcircuit SRX-D.

<Module Configuration of the Liquid Crystal Display Apparatus 1>

FIG. 7 is a schematic plan view showing an overall configuration of amodule 500 mounted with the liquid crystal display apparatus 1. Althoughschematically shown, FIG. 7 shows practical arrangement. In thisdrawing, reference character 501 indicates an area of the TFT glasssubstrate shown in FIGS. 4 and 5, and reference character 502 indicatesan area having the TFT glass substrate and the CF glass substrate shownin FIGS. 4 and 5. In the module 500, the TFT glass substrate isintegrated. That is, the TFT glass substrate is common between the area501 and the area 502, and the CF glass substrate or others are furtherformed on the upper surface of the TFT glass substrate in the area 502as shown in FIGS. 4 and 5.

In FIG. 7, reference character 500-U indicates a short side of themodule 500, and reference character 500-D indicates a side of the module500 which is a short side opposite to the short side 500-U. Also,reference character 500-L indicates a long side of the module 500, andreference character 500-R indicates a side of the module 500 which is along side opposite to the long side 500-L.

The gate driver 5, the selection drive circuit SDC, and the selectioncontrol circuit SR-L shown in FIG. 6 are arranged in an area between theside 2-L of the display panel 2 and the long side 500-L of the module500 in the area 502. Also, the switching circuit DSC and the selectioncontrol circuit SR-R shown in FIG. 6 are arranged in an area between theside 2-R of the display panel 2 and the long side 500-R of the module500. The switching adjustment circuit SCX-U shown in FIG. 6 is arrangedin an area between the side 2-U of the display panel 2 and the shortside 500-U of the module 500.

Also, the signal line selector 3, the switching adjustment circuitSCX-D, the selection control circuit SRX-D, and the semiconductor devicefor drive DDIC shown in FIG. 6 are arranged in an area between the side2-D of the display panel 2 and the short side 500-D of the module 500.

In the first embodiment, the signal line driver D-DRV and the controlcircuit D-CNT shown in FIG. 6 are embedded in one semiconductor device.In the present specification, one semiconductor device is shown as thesemiconductor device for drive DDIC. Also, the touch control device 6shown in FIG. 6 is further embedded in one semiconductor device. In thepresent specification, In order to distinguish from the semiconductordevice for drive DDIC, the semiconductor device in which the touchcontrol device 6 is embedded is called the semiconductor device fortouch 6. Naturally, each of the semiconductor device for drive DDIC andthe semiconductor device for touch 6 may be configured of a plurality ofsemiconductor devices. Also, for example, in the semiconductor devicefor drive DDIC, the switching adjustment circuit SCX-D and the selectioncontrol circuit SRX-D may be embedded.

In the first embodiment, the switching adjustment circuit SCX-D and theselection control circuit SRX-D are arranged in the area 501 andconfigured of wires and components formed in the TFT glass substrate ofthe area 501. As the components, a switching component is cited, and theswitching component is, for example, a thin film transistor(hereinafter, called a TFT transistor). Also, the semiconductor devicefor drive DDIC is mounted on the TFT glass substrate so as to cover theswitching adjustment circuit SCX-D and the selection control circuitSRX-D when seen in plane view. Accordingly, increase in a size of alower frame of the display panel 2 can be suppressed.

Also, components configuring the switching circuit DSC, the selectiondrive circuit SDC, the switching adjustment circuit SCX-U, and theselection control circuits SR-R, SR-L are formed on the TFT glasssubstrate in the area 502.

In FIG. 7, reference characters FB1 and FB2 indicate flexible cables.Although not specifically limited, the semiconductor device for touch 6is mounted on the flexible cable FB1, and a connector CN is mounted onthe flexible cable FB2. The sense signals S(0) to S(p) described withreference to FIG. 6 are supplied from the selection control circuitSRX-D to the semiconductor device for touch 6 via the connector CN.Further, via the connector CN, signals are transmitted and receivedbetween the semiconductor device for touch 6 and the semiconductordevice for drive DDIC. In FIG. 7, the synchronizing signal TSHD is shownas an example of signals that are transmitted and received.

As described above, the display panel 2 includes, a pixel array in whicha plurality of pixels are arranged in a matrix form, and the pixel arrayincludes the plurality of drive electrodes TL(0) to TL(p) and scanninglines GL(0) to GL(p) arranged along the row of the array and a pluralityof signal lines SL(0) to SL(p) arranged along the column of the array.FIG. 7 shows two drive electrodes TL(n), TL(m) and two signal wiresSL(k), SL(n) as an example. Note that the scanning lines are omitted inFIG. 7. Pixels are arranged in intersecting portions between the signallines SL(0) to SL(p) and the scanning lines or the drive electrodesTL(0) to TL(p). Reference characters R, G, and B explicitly shown onfour sides of the display panel 2 shown in FIG. 7 indicate pixelscorresponding to three primary colors.

FIG. 8 is a plan view showing the relation between the drive electrodesand signal lines included in the display panel 2. The display panel 2includes the drive electrodes TL(0) to TL(p) and the signal lines SL(0)to SL(p). In FIG. 8, some of these drive electrodes and signal lines areshown as the drive electrodes TL(n−6) to TL(n+9) and the signal linesSL(n−6) to SL(n+9). In FIG. 8, note that the scanning lines are omitted.

In explanation of the drive electrode made by exemplifying the driveelectrodes TL(n−6) to TL(n+9) shown in FIG. 8, each drive electrodeincludes a first electrode and a plurality of second electrodesconnected to the first electrode. Here, the first electrode is, forexample, a transparent electrode, and the second electrode is anelectrode having a sheet resistance lower than that of the firstelectrode. In FIG. 8, one second electrode of the plurality of secondelectrodes included in each drive electrode is shown as an auxiliaryelectrode SM. In order to avoid the complexity of the drawing, in FIG.8, the reference character SM is attached to only auxiliary electrodesincluded in the drive electrodes TL(n−6), TL(n+9).

As similar to the first electrode (transparent electrode) configuringthe drive electrode, the auxiliary electrode SM extends in the rowdirection of the array and is electronically connected to the firstelectrode. Accordingly, a combined resistance (impedance) of the driveelectrode including the first electrode and the auxiliary electrode(second electrode) can be reduced. In the present specification, thefirst electrode (transparent electrode) and the second electrode(auxiliary electrode SM) connected to the first electrode are combinedand called the drive electrode unless otherwise specified.

In FIG. 8, note that reference characters U(−6) to U(+9) and D(−6) toD(+9) are reference characters to indicate connection to the switchingadjustment circuits SCX-U, SCX-D described below.

<Structure of the Display Panel>

FIG. 9 is a cross-sectional view showing the configuration of thedisplay panel 2 included in the liquid crystal display apparatus 1according to the first embodiment. From the viewpoint of display, thearea (first area) of the display panel 2 is an active area where adisplay is produced. On the other hand, an area (second area) outsidethe display panel 2 is an area where no display is produced, and can beconsidered to be a non-active area or a peripheral area. In explanationwith reference to FIG. 7 as an example, the active area is an areasurrounded by the sides 2-U, 2-D, 2-R, 2-L of the display panel 2.

FIG. 9 shows an A-A′ cross section of the display panel 2 shown in FIG.7. In the first embodiment, in order to produce a color display, onecolor pixel is displayed by using three pixels corresponding to threeprimary colors of R(red), G(green), and B(blue). That is, one colorpixel can be considered to be formed of three sub-pixels. In this case,in the display period, signal lines that transfer a color image signalare formed of three signal lines. In order to show a concrete structureof the display panel 2, FIG. 9 shows an example of producing the colordisplay.

Before the explanation of FIG. 9, reference characters of the signallines used in FIG. 9 will be described. Each of the signal lines SL(0)to SL(p) indicates a signal line that transfers a color image signal ina display period. Each signal line includes three signal lines thattransfer an image signal to three sub-pixels. In FIG. 9, the threesignal lines are distinguished from one another by attaching analphabetical character of the corresponding sub-pixel to the end of thereference character of the signal line. When the signal line SL(n) isexemplified, the signal line SL(n) includes signal lines SL(n)R, SL(n)G,SL(n)B. Here, the alphabetical character “R” attached to the end of thereference character SL(n) indicates a signal line that transfers animage signal to a sub-pixel corresponding to red (R) of the threeprimary colors, the alphabetical character “G” attached to the end ofthe reference character SL(n) indicates a signal line that transfers animage signal to a sub-pixel corresponding to green (G) of the threeprimary colors, and the alphabetical character “B” attached to the endof the reference character SL(n) indicates a signal line that transfersan image signal to a sub-pixel corresponding to blue (B) of the threeprimary colors.

In FIG. 9, reference character 600 indicates a TFT glass substrate. Onthe TFT glass substrate 600, a first wiring layer (metallic wire layer)601 is formed. The scanning line GL(n) is configured of a wire formed inthe first wiring layer 601. An insulating layer 602 is formed on thefirst wiring layer 601, and a second wiring layer (metallic wire layer)603 is formed on the insulating layer 602. Signal lines SL(n)R, SL(n)G,SL(n)B, signal lines SL(n+1)R, SL(n+1)G, SL(n+1)B, and signal linesSL(n+2)R, SL(n+2)G are configured of a wire formed in the second wiringlayer 603. In this drawing, in order to show the fact that these signallines are configured of the second wiring layer 603, reference character603 indicating the second wiring layer is attached to the end of thesignal line in parenthesis [ ]. For example, the signal line SL(n)G isindicated as SL(n)G[603].

An insulating layer 604 is formed on the second wiring layer 603, and athird wiring layer (metallic wire layer) 605 is formed on the insulatinglayer 604. The drive electrode TL(n) and the auxiliary electrode SM areconfigured of a wire formed in the third wiring layer 605. Here, thedrive electrode TL(n) is a transparent electrode (first electrode). Theauxiliary electrode SM (secondary electrode) has a resistance valuelower than that of the drive electrode TL(n) and is formed so as to beelectrically connected to the drive electrode TL(n). The resistancevalue of the drive electrode TL(n) which is a transparent electrode isrelatively high. However, by electrically connecting the auxiliaryelectrode SM to the drive electrode TL(n), the combined resistance canbe reduced. Also here, a reference character [605] attached to thereference characters of the drive electrode and the auxiliary electrodeindicates that they are configured of the third wiring layer 605.

An insulating layer 606 is formed on the third wiring layer 605, and apixel electrode LDP is formed on the top surface of the insulating layer606. In FIG. 9, each of CR, CB, and CG is a color filter. A liquidcrystal layer 607 is sandwiched between the color filters CR(red),CG(green), CB(blue) and the insulating layer 606. Here, the pixelelectrode LDP is provided at an intersection between a scanning line anda signal line, and the color filter CR, CG, or CB corresponding to eachof the pixel electrodes LDP is provided above each pixel electrode LDP.A black matrix BM is provided between the color filters CR, CG, CB.

Although omitted in FIG. 9, a CF glass substrate is formed on the colorfilters CR, CG, CB as shown in FIGS. 4 and 5. Further, on the CF glasssubstrate, a light polarizing plate is arranged as shown in FIG. 5.

<Pixel Array>

Next, the circuit configuration of the display panel 2 will bedescribed. FIG. 10 is a circuit diagram showing a circuit configurationof the display panel 2 shown in FIG. 7. Also in FIG. 10, a signal lineis shown in the same form as in FIG. 9. In this drawing, each of aplurality of SPix indicated by an alternate long and short dash lineshows one liquid crystal display element (sub-pixel). The sub-pixel SPixis arranged in a matrix form in the display panel 2 to configure aliquid crystal element array (pixel array) LCD. The pixel array LCDincludes a plurality of the scanning lines GL(0) to GL(p) arranged ineach row and extending in the row direction and signal lines SL(0)R,SL(0)G, SL(0)B to SL(p)R, SL(p)G, SL(p)B arranged in each column andextending in the column direction. The pixel array LCD also includes thedrive electrodes TL(0) to TL(p) arranged in each row and extending inthe row direction.

FIG. 10 shows only pixel array portions related to the scanning linesGL(n−1) to GL(n+1), the signal lines SL(n)R, SL(n)G, SL(n)B to SL(n+1)R,SL(n+1)G, SL(n+1)B, and to the drive electrodes TL(n−1) to TL(n+1). Inorder to facilitate the description, FIG. 10 shows the drive electrodesTL(n−1) to TL(n+1) so as to be arranged in respective rows. However, onedrive electrode may be arranged in a plurality of rows.

Each sub-pixel SPix arranged at an intersection of a row and a column ofthe pixel array LCD includes a TFT transistor Tr formed on the TFT glasssubstrate 600 and a liquid crystal element LC whose one terminal isconnected to the source of the TFT transistor Tr. In the pixel arrayLCD, gates of the TFT transistors Tr of the plurality of sub-pixels SPixarranged in the same row are connected to the scanning line arranged inthe same row, and drains of the TFT transistors Tr of the plurality ofsub-pixels SPix arranged in the same column are connected to the signalline arranged in the same column. In other words, the plurality ofsub-pixels SPix is arranged in a matrix form, a scanning line isarranged in each row, and the plurality of sub-pixels SPix arranged inthe corresponding row is connected to the scanning line. Also, a signalline is arranged in each column, and the pixels SPix arranged in thecorresponding column are connected to the signal line. The other ends ofthe liquid crystal elements LC of the plurality of sub-pixels SPixarranged in the same row are connected to the drive electrode arrangedin the row.

In the description of the example shown in FIG. 10, in this drawing, thegate of the TFT transistor Tr of each of the plurality of sub-pixelsSPix arranged in the top row is connected to the scanning line GL(n−1)arranged in the top row. In this drawing, the drain of the TFTtransistor Tr of each of the plurality of sub-pixels SPix arranged inthe leftmost column is connected to the signal line SL(n)R arranged inthe leftmost column. Further, in FIG. 10, the other end of the liquidcrystal element LC of each of the plurality of sub-pixels SPix arrangedin the top row is connected to the drive electrode TL(n−1) arranged inthe top row.

As described above, one sub-pixel SPix corresponds to one of the threeprimary colors. Thus, the three primary colors of R, G, and B are formedof three sub-pixels SPix. In FIG. 10, one color pixel Pix is formed ofthree sub-pixels SPix arranged consecutively in the same row, and colorsare expressed by the pixel Pix. That is, in FIG. 10, the sub-pixel SPixindicated as a reference character 700R becomes a sub-pixel SPix(R) ofR(red), the sub-pixel SPix indicated as a reference character 700Gbecomes a sub-pixel SPix(G) of G(green), and the sub-pixel SPixindicated as a reference character 700B becomes a sub-pixel SPix(B) ofB(blue). Thus, the sub-pixel SPix(R) indicated by the referencecharacter 700R is provided with a red color filter CR as a color filter,the sub-pixel SPix(G) indicated by the 700G is provided with a greencolor filter CG as a color filter, and the sub-pixel SPix(B) indicatedby the 700B is provided with a blue color filter CB as a color filter.

An image signal corresponding to R of a signal representing one pixel issupplied to the signal line SL(n)R from the signal line selector 3, animage signal corresponding to G is supplied from the signal lineselector 3 to the signal line SL(n)G, and an image signal correspondingto B is supplied from the signal line selector 3 to the signal lineSL(n)B.

Although not specifically limited, the TFT transistor Tr in eachsub-pixel SPix is, an N-channel TFT transistor. To the scanning linesGL(0) to GL(p), for example, pulse-state scanning line signals whoselevels are successively set to a higher level in this order of thescanning lines are supplied from the gate driver 5 (FIGS. 6 and 7). Thatis, in the pixel array LCD, the voltages of scanning lines aresuccessively set to a higher level from the scanning line GL(0) arrangedin the top row toward the scanning line GL(p) arranged in the bottomrow. Accordingly, in the pixel array LCD, the TFT transistors Tr in thesub-pixels SPix are successively conducted from the sub-pixel SPixarranged in the top row toward the sub-pixel SPix arranged in the bottomrow.

By the state in which the TFT transistor Tr is conducted, the imagesignal supplied to the signal line at that time is supplied to theliquid crystal element LC via the conduction-state TFT transistor. Theelectric field of the liquid crystal element LC changes depending on adifferential voltage between the voltage of a display drive signalsupplied to the drive electrodes TL(0) to TL(p) and the voltage of asupplied image signal, so that the modulation of light passing throughthe liquid crystal element LC thereof changes. Accordingly, a colorimage in accordance with an image signal supplied to the signal linesSL(0)R, SL(0)G, SL(n)B to SL(p)R, SL(p)G, SL(p)B in synchronization withscanning line signals supplied to the scanning lines GL(0) to GL(p) isdisplayed in the display panel 2.

Each of the plurality of sub-pixels SPix can be considered to have aselection terminal and a pair of terminals. In this case, the gate ofthe TFT transistor Tr configuring the sub-pixel SPix is the selectionterminal of the sub-pixel SPix, the drain of the TFT transistor Tr isone terminal of the pair of terminals, and the other end of the liquidcrystal element LC is the other terminal of the sub-pixel SPix.

Here, the correspondence between the arrangement of the display panel 2shown in FIGS. 6 and 7 and the circuit diagram shown in FIG. 10 will bedescribed as follows.

The pixel array LCD has a pair of sides substantially parallel to therow of the array thereof and has a pair of sides substantially parallelto the column of the array thereof. The paired sides that are parallelto the row of the pixel array LCD are a first side and a second sidecorresponding to the short sides 2-U, 2-D of the display panel 2 shownin FIGS. 6 and 7, and the paired sides that are parallel to the columnof the pixel array LCD are a third side and a fourth side correspondingto the long sides 2-L, 2-R of the display panel 2.

In the pixel array LCD, as shown in FIG. 7, the signal line selector 3,the switching adjustment circuit SCX-D, the selection control circuitSRX-D, and the semiconductor device for drive DDIC are arranged alongthe second side of the pair of sides parallel to the row, that is, theone short side 2-D of the display panel 2. In the pixel array LCD, inthe second side (short side 2-D of the liquid crystal panel 2), an imagesignal from the semiconductor device for drive DDIC is supplied to thesignal lines SL(0)R, SL(0)G, SL(0)B to SL(p)R, SL(p)G, SL(p)B via thesignal line selector 3.

Also, as shown in FIG. 7, the switching adjustment circuit SCX-U isarranged along the first side of the pixel array LCD, that is, the otherside (short side 2-U) of the display panel 2.

In the pixel array LCD, the gate driver 5, the selection control circuitSR-L, and the selection drive circuit SDC are arranged along the thirdside of the pair of sides (third and fourth sides) parallel to thecolumn, that is, the long side 2-L of the display panel 2. In the pixelarray LCD, a scanning line signal from the gate driver 5 is supplied tothe scanning lines GL(0) to GL(p) on the third side. In FIG. 7, the gatedriver 5 is arranged along the long side 2-L of the display panel 2.However, the gate driver 5 may be divided into two units and be arrangedalong the long side 2-L (third side of the pixel array LCD) and the longside 2-R (fourth side of the pixel array LCD). Also in the pixel arrayLCD, a display drive signal is supplied from the selection drive circuitSDC to drive electrodes on the third side in a display period, and amagnetic-field drive signal is supplied from the selection drive circuitSDC to a plurality of assigned drive electrodes on the third side in themagnetic field generation period TGT in a touch detection period.

As shown in FIG. 7, the switching circuit DSC and the selection controlcircuit SR-R are arranged along the fourth side of the pixel array LCD,that is, the long side 2-R of the display panel 2. In a display period,a display drive signal from the switching circuit DSC is supplied to thecommon electrode on the fourth side. In a touch detection period, aplurality of drive electrodes are electrically connected on the fourthside.

The pixel array LCD caused when a color display is produced in thedisplay panel 2 has been concretely described, and the pixel array LCDmay be considered to be configured of a plurality of color pixels Pix(pixel), each of which is configured of three sub-pixels SPix. Whenconsidered as described above, the plurality of pixels Pix are arrangedin a matrix form to configure the pixel array LCD. The correspondingscanning lines GL(0) to GL(p) and the corresponding drive electrodesTL(0) to TL(p) are arranged in the respective rows of the pixel arrayLCD configured of pixels Pix, and the signal lines SL(0) to SL(p) arearranged in the respective columns thereof.

In this case, three sub-pixels SPix are considered to be one pixel Pix,and the pixel Pix is considered to have a configuration similar to thatof the sub-pixel SPix. The respective selection terminals of pixels Pixarranged in a matrix form in the pixel array LCD are connected to thescanning line GL(0) to GL(p) arranged in the same row as the pixel Pix,one respective terminals of pixels Pix are connected to the signal lineSL(0) to SL(p) arranged in the same column, and the other respectiveterminals of pixels Pix are connected to the drive electrode TL(0) toTL(p) arranged in the same column. Naturally, one drive electrode maycorrespond to a plurality of rows of the pixel array LCD. In such acase, the other terminal of the pixel Pix arranged in the plurality ofrows is connected to the common drive electrode.

Also when the pixel array LCD is considered to be configured of theplurality of pixels Pix as described above, the correspondence betweenthe arrangement of the display panel 2 shown in FIGS. 6 and 7 and thecircuit diagram shown in FIG. 10 is the same as described above.

A case in which the number of sub-pixels SPix configuring one colorpixel Pix is three has been described. However, the present embodimentis not limited to such an example. For example, one color pixel may beformed of sub-pixels of, in addition to R, G, B described above, any onecolor or a plurality of colors of white (W) and yellow (Y) and alsocomplementary colors of R, G, B (cyan (C), magenta(M), and yellow (Y)).

<Electrode Drive Circuit>

Next, an electrode drive circuit (the selection control circuits SR-R,SR-L, the switching circuit DSC, and the selection drive circuit SDC) inthe liquid crystal display apparatus 1 according to the first embodimentwill be described using FIGS. 11 to 15.

<<Operation Overview of the Electrode Drive Circuit>>

In order to facilitate the understanding of the electrode drive circuit,an operation overview will be first described. In the first embodiment,four drive electrodes are assigned from the plurality of driveelectrodes TL(0) to TL(p) in the magnetic field generation period TGT.Each two of the four assigned drive electrodes becomes one bundle(pair), so that two bundles are formed. In each bundle, an end of onedrive electrode and an end of the other drive electrode are mutuallyconnected electrically. The drive electrodes are arranged in parallelwith each other. Therefore, by electrically connecting ends thereof, acoil formed of drive electrodes as a wire winding in each bundle isformed. One coil is formed of one bundle, and thus, two coils are formedof four drive electrodes.

When four drive electrodes are assigned, drive electrodes are assignedso that inner sides of coils mutually overlap between the two formedcoils. In other words, if the two bundles are denoted as a first bundleand a second bundle, drive electrodes are assigned so that an area(drive electrode) sandwiched between two drive electrodes configuringthe first bundle and an area (drive electrode) sandwiched between twodrive electrodes configuring the second bundle overlap.

To the two formed coils, the coil clock signals synchronized with eachother are supplied substantially simultaneously as magnetic-field drivesignals. Accordingly, in an overlapped area (area corresponding to driveelectrodes), a magnetic field generated by the coil formed of driveelectrodes of the first bundle and a magnetic field generated by thecoil formed of drive electrodes of the second bundle are superimposed.Each of coils formed of the first bundle and the second bundle is asingle-winding coil. Therefore, even if the sheet resistance of thedrive electrode is relatively high, the formed coil is relatively shortin length, and thus, increase in the impedance of the coil can beprevented, and therefore, decrease in a drive current flowing throughthe coil in synchronization with the coil clock signal can be prevented.As a result, while inhibiting a magnetic field generated per coil fromweakening, the magnetic field in an overlapped area can be made strongerby superimposing magnetic fields.

Also in the first embodiment, an area corresponding to two driveelectrodes close to each other is set as an area where coils mutuallyoverlap. In the predetermined magnetic field generation period TGT, twocoils are formed of four drive electrodes arranged so as to sandwich anarea of two drive electrodes close to each other, and a magnetic fieldis generated in the area of two drive electrodes close to each other. Ina next magnetic field generation period TGT, the two drive electrodesclose to each other are assigned as drive electrodes configuring twobundles. In a next magnetic field generation period TGT, two coils areformed of two bundles including the assigned drive electrodes togenerate a magnetic field. Accordingly, the drive electrodescorresponding to an overlapped area are used as a coil winding wire togenerate a magnetic field in the next magnetic field generation periodTGT. By successively assigning drive electrodes corresponding to anoverlapped area to use as a coil winding wire in the next magnetic fieldgeneration period TGT as described above, whether the display panel 2 istouched or the touched position of the display panel 2 can be scanned.

By performing such a scan, an area (overlapped area) where the touch isto be detected and an area where the coil is shifted in this scan can bethe same as each other in size, so that generation of an area where nomagnetic field in this scan van be prevented, so that generation of anarea where the accuracy of detection of the touch is degraded can beprevented. In description along the first embodiment, an overlapped areain a scan corresponds to two drive electrodes, and the coil is shifted(moved) in units of two bundles.

<<Configuration of the Electrode Drive Circuit>>

FIG. 11 is a block diagram showing the configuration of the liquidcrystal display apparatus 1 according to the first embodiment. Thisdrawing shows a configuration of the drive electrodes TL(0) to TL(p) anda portion of the electrode drive circuit (the selection control circuitsSR-R, SR-L, the switching circuit DSC, and the selection drive circuitSDC) corresponding to the drive electrodes TL(n−2) to TL(n+7) of thesedrive electrodes. As described above, note that each drive electrodeincludes the first electrode (transparent electrode) and the secondelectrode (auxiliary electrode). In order to explicitly show this inFIG. 11, a solid line with the reference character of the auxiliaryelectrode SM is representatively shown in the drive electrodes TL(0),TL(p).

<<The Selection Control Circuit SR-R and the Switching Circuit DSC>>

Although not specifically limited, the selection control circuit SR-R inthe first embodiment includes a shift register. The operation of touchdetection of the shift register is instructed by the magnetic-fieldenable signal SC_EN, and performs a shift operation in synchronizationwith changes of the clock signal CLK by a state in which the controlsignal Y-CNT becomes, for example, a high level. The selection controlcircuit SR-R includes a plurality of unit selection circuitscorresponding to each step of the shift register. When the operation oftouch detection is assigned, a high-level selection signal correspondingto the logical value “1” is successively output from the plurality ofunit selection circuits in synchronization with changes of the clocksignal CLK. In the first embodiment, each of the plurality of unitselection circuits is in a one-to-one correspondence with an area wherea strong magnetic field is generated. In the first embodiment, each areawhere a strong magnetic field is generated corresponds to two driveelectrodes arranged close to each other. Thus, the selection controlcircuit SR-R includes the plurality of unit selection circuits each ofwhich is in a one-to-one correspondence with two drive electrodes each.

In FIG. 11, the drive electrode TL(n) and the drive electrode TL(n+1)correspond to one area where a strong magnetic field is generated.Similarly, the drive electrode TL(n+2) and the drive electrode TL(n+3)correspond to one area where a strong magnetic field is generated, thedrive electrode TL(n+4) and the drive electrode TL(n+5) correspond toone area where a strong magnetic field is generated, the drive electrodeTL(n+6) and the drive electrode TL(n+7) correspond to one area where astrong magnetic field is generated, and the drive electrode TL(n−2) andthe drive electrode TL(n−1) correspond to one area where a strongmagnetic field is generated.

FIG. 11 shows, among the plurality of unit selection circuitsconfiguring the selection control circuit SR-R, the unit selectioncircuits USR(n−2) to USR(n+6) corresponding to areas where a strongmagnetic field is generated. That is, the unit selection circuit USR(n)corresponds to an area corresponding to the drive electrode TL(n) andthe drive electrode TL(n+1). Similarly, the unit selection circuitUSR(n+2) corresponds to an area corresponding to the drive electrodeTL(n+2) and the drive electrode TL(n+3), and the unit selection circuitUSR(n+4) corresponds to an area corresponding to the drive electrodeTL(n+4) and the drive electrode TL(n+5). Also, the unit selectioncircuit USR(n+6) corresponds to an area corresponding to the driveelectrode TL(n+6) and the drive electrode TL(n+7), and the unitselection circuit USR(n−2) corresponds to an area corresponding to thedrive electrode TL(n−2) and the drive electrode TL(n−1).

In a touch detection period, the unit selection circuits USR(n−2),USR(n), USR(n+2), USR(n+4), USR(n+6) output selection signals Ty(n−2)R,Ty(n)R, Ty(n+2)R, Ty(n+4)R, Ty(n+6)R in synchronization with the clocksignal CLK, respectively. The selection signals Ty(n−2)R to Ty(n+6) fromthe unit selection circuits USR(n−2) to USR(n+6) are supplied to theswitching circuit DSC.

The switching circuit DSC includes signal wires LL1, LL2, a voltage wireVL1, and first switches a00 to a09. Here, the signal wires LL1, LL2 areused as signal wires to electrically connect drive electrodes in a touchdetection period. The display drive signal VCOMDC is supplied to thevoltage wire VL1 in a display period. The value of the display drivesignal VCOMDC is, for example, the ground voltage Vss.

Each of the first switches a00 to a09 includes a common terminal “c”, afirst terminal “p1”, a second terminal “p2”, and a third terminal, andthe common terminal c is connected to any one of the first terminal p1,the second terminal p2, and the third terminal in accordance with theselection signals Ty(n−2)R to Ty(n+6) from the unit selection circuitsUSR(n−2) to USR(n+6). The third terminal of each of the first switchesa00 to a09 is connected to no signal wire, and is in a floating state.Thus, in FIG. 11, the third terminal of each of the first switches a00to a09 is omitted.

The first terminal p1 of each of the first switches a00 to a09 isconnected to the voltage wire VL1. The second terminal p2 of the firstswitches a00, a02, a04, a06, a08 is connected to the signal wire LL1,and the second terminal p2 of the first switches a01, a03, a05, a07, a09is connected to the signal wire LL2.

The common terminal c of the first switch a00 is connected to one end ofthe corresponding drive electrode TL(n−2), the common terminal c of thefirst switch a01 is connected to one end of the corresponding driveelectrode TL(n−1), the common terminal c of the first switch a02 isconnected to one end of the corresponding drive electrode TL(n), thecommon terminal c of the first switch a03 is connected to one end of thecorresponding drive electrode TL(n+1), and the common terminal c of thefirst switch a04 is connected to one end of the corresponding driveelectrode TL(n+2). Similarly, the common terminal c of the first switcha05 is connected to one end of the corresponding drive electrodeTL(n+3), the common terminal c of the first switch a06 is connected toone end of the corresponding drive electrode TL(n+4), the commonterminal c of the first switch a07 is connected to one end of thecorresponding drive electrode TL(n+5), the common terminal c of thefirst switch a08 is connected to one end of the corresponding driveelectrode TL(n+6), and the common terminal c of the first switch a09 isconnected to one end of the corresponding drive electrode TL(n+7).

The first switch a00 and the first switch a01 are controlled as a pair.That is, the first switches a01, a02 are controlled by the selectionsignal Ty(n)R from the unit selection circuit USR(n) and a selectionsignal Ty(n−4)R from a unit selection circuit USR(n−4) not shown. Thefirst switches a02, a03 are set as a pair and are controlled by theselection signal Ty(n−2)R from the unit selection circuit USR(n−2) andthe selection signal Ty(n+2)R from the unit selection circuit USR(n+2),and the first switches a04, a05 are set as a pair and are controlled bythe selection signal Ty(n)R from the unit selection circuit USR(n) andthe selection signal Ty(n+4)R from the unit selection circuit USR(n+4).Similarly, the first switches a06, a07 are set as a pair and arecontrolled by the selection signal Ty(n+2)R from the unit selectioncircuit USR(n+2) and the selection signal Ty(n+6)R from the unitselection circuit USR(n+6), and the first switches a08, a09 are set as apair and are controlled by the selection signal Ty(n+4)R from the unitselection circuit USR(n+4) and the selection signal Ty(n+8)R from theunit selection circuit USR(n+8).

If a magnetic-field drive signal is supplied to a coil in the magneticfield generation period TGT, a strong magnetic field is generated insidethe coil. Thus, the selection signal formed by the unit selectioncircuit corresponding to two drive electrodes is used as a selectionsignal that electrically connects drive electrodes arranged so as tosandwich the two drive electrodes therebetween. In the description whileexemplifying the unit selection circuit USR(n) corresponding to thedrive electrode TL(n) and the drive electrode TL(n+1), in the magneticfield generation period TGT, the selection signal Ty(n)R formed by theunit selection circuit USR(n) is used as a selection signal thatelectrically connects the drive electrodes TL(n−2), TL(n−1) and thedrive electrodes TL(n+2), TL(n+3) arranged so as to sandwich the driveelectrodes TL(n), TL(n+1) therebetween so that a strong magnetic fieldis generated in an area of the corresponding drive electrodes TL(n),TL(n+1).

In the first embodiment, as described in the overview above, four driveelectrodes are assigned in the magnetic field generation period TGT, onebundle is formed of each two drive electrodes of the assigned driveelectrodes to generate a magnetic field using two bundles as a unit.When a strong magnetic field is generated in an area of the driveelectrodes TL(n), TL(n+1), the selection signal Ty(n)R formed by theunit selection circuit USR(n) assigns the drive electrodes TL(n−2),TL(n−1), TL(n+2), TL(n+3). The selection signal Ty(n)R controls thefirst switches a00, a01, a04, a05 so that one bundle (first bundle) isformed of the drive electrodes TL(n−2), TL(n+2) and one bundle (secondbundle) is formed of the drive electrodes TL(n−1), TL(n+3). That is, bythe selection signal Ty(n)R, the common terminal c of each of the firstswitches a00, a01, a04, a05 is controlled to be connected to the secondterminal p2.

Accordingly, the drive electrode TL(n−2) is connected to the signal wireLL1 via the first switch a00 and the drive electrode TL(n+2) isconnected to the signal wire LL1 via the first switch a04. As a result,the drive electrodes TL(n−2), TL(n+2) are electrically connected to eachother, and a coil CY(n) having these drive electrodes as a winding wireis formed. Similarly, the drive electrode TL(n−1) is connected to thesignal wire LL2 via the first switch a01, and the drive electrodeTL(n+3) is connected to the signal wire LL2 via the first switch a05. Asa result, the drive electrodes TL(n−1), TL(n+3) are electricallyconnected to each other, and a coil CY(n+1) having these driveelectrodes as a winding wire is formed.

In this case, the area of a magnetic field, that is, the area of thecoil generated by the coil CY(n) is an area sandwiched between the driveelectrode TL(n−2) and the drive electrode TL(n+2) and is an areacorresponding to the drive electrodes TL(n−1) to TL(n+1). On the otherhand, the area of a magnetic field, that is, the area of the coilgenerated by the coil CY(n+1) is an area sandwiched between the driveelectrode TL(n−1) and the drive electrode TL(n+3) and is an areacorresponding to the drive electrodes TL(n) to TL(n+2). Therefore, thearea of the coil CY(n) and the area of the CY(n+1) overlap with eachother in an area corresponding to the drive electrodes TL(n), TL(n+1).

When a strong magnetic field is generated in an area of the driveelectrodes TL(n+2), TL(n+3), four drive electrodes TL(n), TL(n+1),TL(n+4), TL(n+5) are assigned by the selection signal Ty(n+2)R formed bythe unit selection circuit USC(n+2) corresponding to the driveelectrodes TL(n+2), TL(n+3), and the common terminal c of each of thefirst switches a02, a03, a06, a07 is connected to the second terminalp2. Accordingly, the drive electrodes TL(n), TL(n+4) are electricallyconnected to form a coil CY(n+2), and the drive electrodes TL(n+1),TL(n+5) are electrically connected to form a coil CY(n+3). In this case,an area where an area of the coil CY(n+2) and an area of the coilCY(n+3) overlap with each other is an area corresponding to the driveelectrodes TL(n+2), TL(n+3).

Similarly, when a strong magnetic field is generated in an area of thedrive electrodes TL(n+4), TL(n+5), four drive electrodes TL(n+2),TL(n+3), TL(n+6), TL(n+7) are assigned by the selection signal Ty(n+4)Rformed by the unit selection circuit USC(n+4) corresponding to the driveelectrodes TL(n+4), TL(n+5), and the common terminal c of each of thefirst switches a04, a05, a08, a09 is connected to the second terminalp2. Accordingly, the drive electrodes TL(n+2), TL(n+6) are electricallyconnected to form a coil CY(n+4), and the drive electrodes TL(n+3),TL(n+7) are electrically connected to form a coil CY(n+5). In this case,an area where an area of the coil CY(n+4) and an area of the coilCY(n+5) overlap with each other is an area corresponding to the driveelectrodes TL(n+4), TL(n+5).

Other drive electrodes are similarly handled. That is, two coils areformed of drive electrodes assigned by a selection signal formed by aunit selection circuit. In this case, the two formed coils have an areawhere the coils overlap with each other. In the first embodiment, theunit selection circuit can be considered to assign an area where twoformed coils overlap with each other.

In FIG. 11, in order to avoid the complexity of the drawing, each of theselection signals Ty(n−2)R, Ty(n)R, Ty(n+2)R, Ty(n+4)R, Ty(n+6)R isshown as one signal. However, each of the selection signals is formed ofa plurality of selection signals. In the description of the selectionsignal Ty(n)R as an example, the selection signal Ty(n)R includes adisplay selection signal Ty(n)R−1 that selects whether to connect thecommon terminal c of the first switches a00, a01, a04, a05 to the firstterminal p1 and a touch selection signal Ty(n)R−2 that selects whetherto connect the common terminal c of the first switches a00, a01, a04,a05 to the second terminal p2 or the third terminal.

Similarly, each of the other selection signals Ty(n−2)R, Ty(n+2)R,Ty(n+4)R, Ty(n+6)R includes a display selection signal (referencecharacter of −1 is attached to the reference character of the selectionsignal) and a touch selection signal (reference character of −2 isattached to the reference character of the selection signal). In furtherdescription of the selection signal Ty(n+2)R as an example, theselection signal Ty(n+2)R includes a display selection signal Ty(n+2)R−1that selects whether to connect the common terminal c of the firstswitches a02, a03, a06, a07 to the first terminal p1 and a touchselection signal Ty(n+2)R−2 that selects whether to connect the commonterminal c of the first switches a02, a03, a06, a07 to the secondterminal p2 or the third terminal.

In touch detection, the control circuit D-CNT in the semiconductordevice for drive DDIC sets the magnetic-field enable signal SC_EN to,for example, a high level, and the control signal Y-CNT to, for example,the high level. The clock signal CLK changes periodically, so that thetouch selection signal output from the selection control circuit SR-Ris, for example, successively set to the high level.

In description using FIG. 11 as an example, the touch selection signalTy(n−2)R−2 output from the unit selection circuit USR(n−2) becomes atthe high level first. At this time, the other touch selection signalsTy(n)R−2, Ty(n+2)R−2, Ty(n+4)R−2, Ty(n+6)R−2 are at a low level. Whenthe clock signal CLK changes, the touch selection signal Ty(n)R−2 outputfrom the unit selection circuit USR(n) changes to the high level, andthe other touch selection signals Ty(n−2)R−2, Ty(n+2)R−2, Ty(n+4)R−2,Ty(n+6)R−2 are at the low level. Hereinafter, for each change of theclock signal CLK, the touch selection signals Ty(n+2)R−2, Ty(n+4)R−2,Ty(n+6)R−2 successively become at the high level in this order, andtouch selection signals except for the touch selection signals becomingat the high level become at the low level.

By the state in which the magnetic-field enable signal SC_EN becomes atthe low level, the unit selection circuits USR(n−2), USR(n), USR(n+2),USR(n+4), USR(n+6) set the touch selection signals Ty(n−2)R−2, Ty(n)R−2,Ty(n+2)R−2, Ty(n+4)R−2, Ty(n+6)R−2 to the low level, and changes each ofthe display selection signals Ty(n−2)R−1, Ty(n)R−1, Ty(n+2)R−1,Ty(n+4)R−1, Ty(n+6)R−1 from the low level to the high level.

In each of the first switches a00 to a09, the common terminal c isconnected to the second terminal p2 by the supplied touch selectionsignal being set to the high level, and the common terminal c isconnected to the third terminal by the touch selection signal being setto the low level. Also in each of the first switches a00 to a09, thecommon terminal c is connected to the first terminal p1 when thesupplied display selection signal is at the high level, and the commonterminal c and the first terminal p1 are set to be non-conduction whenthe display selection signal is at the low level.

The magnetic-field enable signal SC_EN is set to the low level in touchdetection, and the touch selection signals Ty(n)R−2 to Ty(n+6)R−2 aresuccessively set to the high level in this order. Accordingly, asdescribed above, the coils CY(n), CY(n+1) are formed, and then, thecoils CY(n+2), CY(n+3) are formed. After the formation of the coilsCY(n+2), CY(n+3), the coils CY(n+4), CY(n+5) are formed. That is, thecoils are successively formed in each two as a unit.

FIG. 15 is a plan view schematically showing the coils CY(n) to CY(n+6)formed in the magnetic field generation period TGT. FIG. 15 show all thecoils CY(n) to CY(n+6), and the coils are successively formed in eachtwo as a unit along with the elapse of time in the order of the coilsCY(n) and CY(n+1), the coils CY(n+2) and CY(n+3), and the coils CY(n+4)and CY(n+5). In order to easily see the drawings, wires connecting thedrive electrodes are separately shown. However, the signal wires LL1,LL2 shown in FIG. 11 are used as wires connecting the drive electrodes.In order to easily see the drawings, the drive electrodes TL(n+6),TL(n+7) and wires connecting these drive electrodes and the driveelectrodes TL(n+2), TL(n+3) are shown by a broken line.

In FIG. 15, PTL(n−2) to PTL(n+7) indicate the other ends of the driveelectrodes TL(n−2) to TL(n+7), respectively.

Also in FIG. 15, CX(n) to CX(n+5) indicate coils obtained when coils areformed by using the signal lines SL(n−2) to SL(n+7), instead of thedrive electrodes TL(n−2) to TL(n+7). Also by using the signal linesinstead of the drive electrodes, coils can successively be formed ineach two as a unit along with the elapse of time in the order of thecoils CX(n), CX(n+1), coils CX(n+2), CX(n+3), and coils CX(n+4),CX(n+5). In FIG. 15, note that PSL(n−2) to PSL(n+7) indicate ends of thesignal lines SL(n−2) to SL(n+7), respectively.

While a case of touch detection has been described, the magnetic-fieldenable signal SC_EN is set to the low level in a display period, andthus, a display selection signal is set to the high level, and thecommon terminal c is connected to the first terminal p1 in each of thefirst switches a00 to a09. The display drive signal VCOMDC is suppliedto the voltage wire VL1 in a display period, and thus, the display drivesignal VCOMDC is supplied to one end of each of the drive electrodesTL(n−2) to TL(n+7) via the first switches a00 to a09.

In the first switch a02, for example, the connection between the commonterminal c and the second terminal p2 or the third terminal iscontrolled by both of the touch selection signal Ty(n)R−2 and the touchselection signal Ty(n+2)R−2. However, it is only required to connect thecommon terminal c and the second terminal p2 so as to put a priority onthe high level. This also applies to the other first switches.

<<The Selection Control Circuit SR-L and the Selection Drive CircuitSDC>>

Next, the selection control circuit SR-L and the selection drive circuitSDC will be described with reference to FIG. 11. The configuration ofthe selection control circuit SR-L is similar to that of the selectioncontrol circuit SR-R. That is, the selection control circuit SR-Lincludes a shift register so as to set the magnetic-field enable signalSC_EN to the high level, set the control signal Y-CNT to the high level,and set the clock signal CLK to be changed, so that the selectionsignals successively set to the high level are output. Also, theselection control circuit SR-L has a plurality of unit selectioncircuits corresponding to each step of the shift register. FIG. 11 showsthe unit selection circuits USL(n−2), USL(n), USL(n+2), USL(n+4),USL(n+6) among the plurality of unit selection circuits.

As similar to the unit selection circuits configuring the selectioncontrol circuit SR-R, in the magnetic field generation period TGT, eachof the plurality of unit selection circuits configuring the selectioncontrol circuit SR-L is in a one-to-one correspondence with an areawhere a strong magnetic field is generated. In the description of theunit selection circuits shown in FIG. 11 as an example, the unitselection circuit USL(n−2) corresponds to an area of the driveelectrodes TL(n−2), TL(n−1), the unit selection circuit USL(n)corresponds to an area of the drive electrodes TL(n), TL(n+1), and theunit selection circuit USL(n+2) corresponds to an area of the driveelectrodes TL(n+2), TL(n+3). Similarly, the unit selection circuitUSL(n+4) corresponds to an area of the drive electrodes TL(n+4), TL(n+5)and the unit selection circuit USL(n+6) corresponds to an area of thedrive electrodes TL(n+6), TL(n+7). When a magnetic field is generated ina corresponding area in the magnetic field generation period TGT, theunit selection circuits USL(n−2), USL(n), USL(n+2), USL(n+4), USL(n+6)form and output the selection signals Ty(n−2)L, Ty(n)L, TY(n+2)L,Ty(n+4)L, Ty(n+6)L, respectively.

The selection drive circuit SDC includes a signal wire LL3, voltagewires VL1, VL2, and second switches b00 to b09. To the signal wire LL3,the coil clock signal CCLK is supplied from the control circuit D-CNT(FIG. 6) in touch detection. The coil clock signal CCLK is a clocksignal changing in a predetermined period. The display drive signalVCOMDC is supplied to the voltage wire VL1 in a display period. To thevoltage wire VL2, a predetermined voltage such as the ground voltage Vssis supplied in touch detection.

Each of the second switches b00 to b09 includes a common terminal c, afirst terminal p1, a second terminal p2, a third terminal p3, and afourth terminal, and the common terminal c is connected to the firstterminal p1, the second terminal p2, the third terminal p3, or thefourth terminal depending on the supplied selection signal. The fourthterminal of each of the second switches b00 to b09 is connected to nosignal wire as similar to the third terminal of the first switch, and isin a floating state. Thus, the fourth terminal in each of the secondswitches b00 to b09 is omitted. The first terminal p1 of each of thesecond switches b00 to b09 is connected to the voltage wire VL1, thesecond terminal p2 is connected to the signal wire LL3, and the thirdterminal p3 is connected to the voltage wire VL2.

The common terminal c of the second switch b00 is connected to the otherend PTL(n−2) of the corresponding drive electrode TL(n−2), the commonterminal c of the second switch b01 is connected to the other endPTL(n−1) of the drive electrode TL(n−1), the common terminal c of thesecond switch b02 is connected to the other end PTL(n) of the driveelectrode TL(n), and the common terminal c of the second switch b03 isconnected to the other end PTL(n+1) of the drive electrode TL(n+1).Also, the common terminal c of the second switch b04 is connected to theother end PTL(n+2) of the drive electrode TL(n+2), the common terminal cof the second switch b05 is connected to the other end PTL(n+3) of thedrive electrode TL(n+3), the common terminal c of the second switch b06is connected to the other end PTL(n+4) of the drive electrode TL(n+4),and the common terminal c of the second switch b07 is connected to theother end PTL(n+5) of the drive electrode TL(n+5). Similarly, the commonterminal c of the second switch b08 is connected to the other endPTL(n+6) of the drive electrode TL(n+6), and the common terminal c ofthe second switch b09 is connected to the other end PTL(n+7) of thedrive electrode TL(n+7).

By the selection signal Ty(n)L from the unit selection circuit USL(n)and a selection signal Ty(n−4)L from a unit selection circuit USL(n−4)not shown, it is determined to which terminal of the first terminal p1,the second terminal p2, the third terminal p3, and the fourth terminalthe common terminal c in each of the second switches b00, b01 isconnected. Also, by the selection signal Ty(n−2)L from the unitselection circuit USL(n−2) and the selection signal Ty(n+2)L from theunit selection circuit USL(n+2), it is determined to which terminal ofthe first terminal p1, the second terminal p2, the third terminal p3,and the fourth terminal the common terminal c in each of the secondswitches b02, b03 is connected. By the selection signal Ty(n)L from theunit selection circuit USL(n) and the selection signal Ty(n+4)L from theunit selection circuit USL(n+4), it is determined to which terminal ofthe first terminal p1, the second terminal p2, the third terminal p3,and the fourth terminal the common terminal c in each of the secondswitches b04, b05 is connected.

By the selection signal Ty(n+2)L from the unit selection circuitUSL(n+2) and the selection signal Ty(n+6)L from the unit selectioncircuit USL(n+6), it is determined to which terminal of the firstterminal p1, the second terminal p2, the third terminal p3, and thefourth terminal the common terminal c in each of the second switchesb06, b07 is connected. Similarly, by the selection signal Ty(n+4)L fromthe unit selection circuit USL(n+4) and the selection signal Ty(n+8)Lfrom the unit selection circuit USL(n+8), it is determined to whichterminal of the first terminal p1, the second terminal p2, the thirdterminal p3, and the fourth terminal the common terminal c in each ofthe second switches b08, b09 is connected.

In touch detection, the selection control circuit SR-L forms a selectionsignal that assigns four drive electrodes arranged so as to sandwich anarea where a strong magnetic field is generated. In description of FIG.11 as an example, when a strong magnetic field is generated in an areacorresponding to the drive electrodes TL(n), TL(n+1), the unit selectioncircuit USL(n) corresponding to the area forms the selection signalTy(n)L. By the formed selection signal Ty(n)L, the common terminal c ineach of the second switches b00, b01 is connected to the second terminalp2, and the common terminal c in each of the second switches b04, b05 isconnected to the third terminal p3. Accordingly, the coil clock signalCCLK is supplied to the end PTL(n−2) of the drive electrode TL(n−2) viathe second switch b00 as a magnetic-field drive signal, and the coilclock signal CCLK is also supplied to the end PTL(n−2) of the driveelectrode TL(n−2) via the second switch b01 as a magnetic-field drivesignal. At this time, the ground voltage Vss is supplied to the endPTL(n+2) of the drive electrode TL(n+2) via the second switch b04, andthe ground voltage Vss is also supplied to the end PTL(n+3) of the driveelectrode TL(n+3) via the second switch b05.

The same coil clock signal CCLK is supplied to the drive electrodesTL(n−2), TL(n−1) as a magnetic-field drive signal, and thus, themagnetic-field drive signal supplied to the drive electrode TL(n−2) andthe magnetic-field drive signal supplied to the drive electrode TL(n−1)are clock signals having substantially the same phase as each other.Also, the second switches b00, b01 are controlled by the same selectionsignal, and the second switches b04, b05 are controlled by the sameselection signal. Thus, the magnetic-field drive signals having the samephase as each other are supplied to the end PTL(n−2) of the driveelectrode TL(n−2) and the end PTL(n−1) of the drive electrode TL(n−1) atsubstantially the same timing. Also, the ground voltage Vss is suppliedto the end PTL(n+2) of the drive electrode TL(n+2) and the end PTL(n+3)of the drive electrode TL(n+3) at substantially the same timing.

Because the coil CY(n) is formed of the drive electrode TL(n−2) and thedrive electrode TL(n+2), the end PTL(n−2) of the drive electrode TL(n−2)and the end PTL(n+2) of the drive electrode TL(n+2) can be considered tobe ends or terminals of the coil CY(n). Similarly, the end PTL(n−1) andthe end PTL(n+3) can be considered to be ends or terminals of the coilCY(n+1). Hereinafter, the end PTL(n−2) to PTL(n+7) may be called ends orterminals of a coil.

The ground voltage Vss is supplied to the end PTL(n+2) of the coilCY(n), and a magnetic-field drive signal changing periodically issupplied to the end PTL(n−2) of the coil CY(n), and thus, the coil CY(n)generates a magnetic field changing in accordance with themagnetic-field drive signal. In this case, the magnetic field is strongin an area inside the coil CY(n), that is, an area of the driveelectrodes TL(n−1) to TL(n+1). Similarly, the coil CY(n+1) alsogenerates a magnetic field changing in accordance with themagnetic-field drive signal. In this case, the magnetic field is strongin an area inside the coil CY(n+1), that is, in an area of the driveelectrodes TL(n) to TL(n+2).

The magnetic-field drive signals supplied to the coil CY(n) and the coilCY(n+1) are at substantially the same timing and have the same phase aseach other, and thus, change of the magnetic field generated by the coilCY(n) and change of the magnetic field generated by the coil CY(n+1) arethe same as each other. As a result, magnetic fields are superimposed toform a strong magnetic field in an area where the coil CY(n) and thecoil CY(n+1) overlap, that is, an area corresponding to the driveelectrodes TL(n), TL(n+1).

In the foregoing, a case of generation of a magnetic field in an areacorresponding to the drive electrodes TL(n), TL(n+1) has been described.However, a case of generation of a magnetic field in other areas issimilar thereto.

That is, when a magnetic field is generated in an area corresponding tothe drive electrodes TL(n+2), TL(n+3), the common terminal c in thesecond switches b02, b03 is connected to the second terminal p2, and thecommon terminal c in the second switches b06, b07 is connected to thethird terminal p3 by the selection signal Ty(n+2)L from the unitselection circuit USL(n+2). Accordingly, the coil clock signal CCLK issupplied to the ends PTL(n), PTL(n+1) of the drive electrodes TL(n),TL(n+1) at substantially the same timing as magnetic-field drive signalshaving the same phase, and the ground voltage Vss is supplied the endsPTL(n+4), PTL(n+5) of the drive electrodes TL(n+4), TL(n+5). As aresult, the coil CY(n+1) and the coil CY(n+2) generate magnetic fieldschanging so as to be the same as each other in accordance with thesupplied magnetic-field drive signal. An area where the coil CY(n+2) andthe coil CY(n+3) overlap is an area corresponding to the driveelectrodes TL(n+2), TL(n+3), and thus, magnetic fields generated by thecoil CY(n+2) and the coil CY(n+3) are superimposed in this area toproduce a strong magnetic field.

Similarly, when a magnetic field is generated in an area correspondingto the drive electrodes TL(n+4), TL(n+5), by the selection signalTy(n+4)L from the unit selection circuit USL(n+4), the common terminal cin the second switches b04, b05 is connected to the second terminal p2,and the common terminal c in the second switches b08, b09 is connectedto the third terminal p3. Accordingly, the coil clock signal CCLK issupplied to the ends PTL(n+2), PTL(n+3) of the drive electrodes TL(n+2),TL(n+3) at substantially the same timing as magnetic-field drive signalshaving the same phase, and the ground voltage Vss is supplied the endsPTL(n+6), PTL(n+7) of the drive electrodes TL(n+6), TL(n+7). As aresult, the coil CY(n+4) and the coil CY(n+5) generate magnetic fieldschanging so as to be the same as each other in accordance with thesupplied magnetic-field drive signal. An area where the coil CY(n+4) andthe coil CY(n+5) overlap is an area corresponding to the driveelectrodes TL(n+4), TL(n+5), and thus, magnetic fields generated by thecoil CY(n+4) and the coil CY(n+5) are superimposed in this area toproduce a strong magnetic field.

In order to avoid the complexity of the drawing, FIG. 11 shows theselection signals Ty(n−2)L to Ty(n+6)L as one signal. However, each ofthe selection signals includes a plurality of selection signals.

In the description of the selection signal Ty(n)L as an example, theselection signal Ty(n)L includes a display selection signal Ty(n)L−1that selects whether to connect the common terminal c of the secondswitches b00, b01, b04, b05 to the first terminal p1, a first touchselection signal Ty(n)L−2 that selects whether to connect the commonterminal c of the second switches b00, b01 to the second terminal p2 orthe fourth terminal, and a second touch selection signal Ty(n)L−3 thatselects whether to connect the common terminal c of the second switchesb04, b05 to the third terminal p3 or the fourth terminal.

Similarly, each of the other selection signals Ty(n−2)L, Ty(n+2)L,Ty(n+4)L, Ty(n+6)L includes a display selection signal (referencecharacter of −1 is attached to the reference character of the selectionsignal), a first touch selection signal (reference character of −2 isattached to the reference character of the selection signal), and asecond touch selection signal (reference character of −3 is attached tothe reference character of the selection signal).

For example, the selection signal Ty(n+2)L includes a display selectionsignal Ty(n+2)L−1 that selects whether to connect the common terminal cof the second switches b02, b03, b06, b07 to the first terminal p1, afirst touch selection signal Ty(n+2)L−2 that selects whether to connectthe common terminal c of the second switches b02, b03 to the secondterminal p2 or the fourth terminal, and a second touch selection signalTy(n+2)L−3 that selects whether to connect the common terminal c of thesecond switches b06, b07 to the third terminal p3 or the fourthterminal. The selection signal Ty(n+4)L includes a display selectionsignal Ty(n+4)L−1 that selects whether to connect the common terminal cof the second switches b04, b05, b08, b09 to the first terminal p1, afirst touch selection signal Ty(n+4)L−2 that selects whether to connectthe common terminal c of the second switches b04, b05 to the secondterminal p2 or the fourth terminal, and a second touch selection signalTy(n+4)L−3 that selects whether to connect the common terminal c of thesecond switches b08, b09 to the third terminal p3 or the fourthterminal.

As similar to the selection control circuit SR-R, the selection controlcircuit SR-L operates in synchronization with changes of the clocksignal CLK when the magnetic-field enable signal SC_EN is at the highlevel and the control signal Y-CNT is at the high level. That is, thefirst touch selection signal and the second touch selection signaloutput from the selection control circuit SR-R are, for example,successively set to the high level.

In description using FIG. 11 as an example, the first touch selectionsignal Ty(n−2)L−2 and the second touch selection signal Ty(n−2)L−3output from the unit selection circuit USL(n−2) becomes at the highlevel first. At this time, the other first touch selection signalsTy(n)L−2, Ty(n+2)L−2, Ty(n+4)L−2, Ty(n+6)L−2 and the other second touchselection signals Ty(n)L−3, Ty(n+2)L−3, Ty(n+4)L−3, Ty(n+6)L−3 are at alow level.

When the clock signal CLK changes, the first touch selection signalTy(n)L−2 and the second touch selection signal Ty(n)L−3 output from theunit selection circuit USR(n) changes to the high level, and the otherfirst touch selection signals Ty(n−2)L−2, Ty(n+2)L−2, Ty(n+4)L−2,Ty(n+6)L−2 are at the low level. Also, the other second touch selectionsignals Ty(n−2)L−3, Ty(n+2)L−3, Ty(n+4)L−3, Ty(n+6)L−3 are also at thelow level. Hereinafter, for each change of the clock signal CLK, thefirst touch selection signals Ty(n+2)L−2, Ty(n+4)L−2, Ty(n+6)L−2successively become at the high level in this order, and first touchselection signals except for the first touch selection signals becomingat the high level become at the low level. Similarly, the second touchselection signals Ty(n+2)L−3, Ty(n+4)L−3, Ty(n+6)L−3 successively becomeat the high level in this order, and second touch selection signalsexcept for the second touch selection signals becoming at the high levelbecome at the low level.

By the state in which the magnetic-field enable signal SC_EN becomes atthe low level, the unit selection circuits USL(n−2), USL(n), USL(n+2),USL(n+4), USL(n+6) set the first touch selection signals Ty(n−2)L−2,Ty(n)L−2, Ty(n+2)L−2, Ty(n+4)L−2, Ty(n+6)L−2 to the low level, and setthe second touch selection signals Ty(n−2)L−3, Ty(n)L−3, Ty(n+2)L−3,Ty(n+4)L−3, Ty(n+6)L−3 to the low level as well. At this time, the unitselection circuits USL(n−2), USL(n), USL(n+2), USL(n+4), USL(n+6)changes each of the display selection signals Ty(n−2)L−1, Ty(n)L−1,Ty(n+2)L−1, Ty(n+4)L−1, Ty(n+6)L−1 from the low level to the high levelin response to the magnetic-field enable signal SC_EN which is at thelow level.

In each of the second switches b00 to b09, the common terminal c isconnected to the second terminal p2 by the supplied first touchselection signal being set to the high level, and the common terminal cis connected to the fourth terminal by the first touch selection signalbeing set to the low level. Also in each of the second switches b00 tob09, the common terminal c is connected to the third terminal p3 whenthe supplied second touch selection signal is at the high level, and thecommon terminal c is connected to the fourth terminal p3 when the secondtouch selection signal is at the low level. Further, in each of thesecond switches b00 to b09, the common terminal c is connected to thefirst terminal p1 when the supplied display selection signal is at thehigh level, and the common terminal c and the first terminal p1 are setto be non-conduction when the display selection signal is at the lowlevel.

The magnetic-field enable signal SC_EN is set to the low level in touchdetection, and the first touch selection signals Ty(n)L−2 to Ty(n+6)L−2are successively set to the high level in this order. In synchronizationwith this, the second touch selection signals Ty(n)L−3 to Ty(n+6)L−3 aresuccessively set to the high level in this order. Accordingly, asdescribed above, magnetic-field drive signals are supplied to endsPTL(n−2), PTL(n−1) of the coils CY(n), CY(n+1), and the ground voltageVss is supplied to ends PTL(n+2), PTL(n+3). Next, magnetic-field drivesignals are supplied to ends PTL(n), PTL(n+1) of the coils CY(n+2),CY(n+3), and the ground ovltage Vss is supplied to ends PTL(n+4),PTL(n+5). Then, magnetic-field drive signals are supplied to endsPTL(n+2), PTL(n+3) of the coils CY(n+4), CY(n+5), and the ground voltageVss is supplied to ends PTL(n+6), PTL(n+7). That is, magnetic-fielddrive signals and the ground voltage Vss are successively supplied tothe coils in each two as a unit.

Each of the second switches b00 to b09 may be configured by, forexample, three switches. In this case, a first switch is connectedbetween the common terminal c and the first terminal p1 and is broughtinto conduction when a display selection signal is at the high level andis brought into non-conduction when the display selection signal is atthe low level. A second switch is connected between the common terminalc and the second terminal p2 and is brought into conduction when a firsttouch selection signal is at the high level and is brought intonon-conduction when the first touch selection signal is at the lowlevel. A third switch is connected between the common terminal c and thethird terminal p3 and is brought into conduction when a second touchselection signal is at the high level and is brought into non-conductionwhen the second touch selection signal is at the low level.

The selection control circuit SR-R and the selection control circuitSR-L operate in synchronization with each other. That is, the unitselection circuits USR(n−2) to USR(n+6) and the unit selection circuitsUSL(n−2) to USL(n+6) output selection signals in synchronization. Forexample, when the unit selection circuit USR(n) outputs a touchselection signal having the high level, the unit selection circuitUSL(n) also outputs a first touch selection signal and a second touchselection signal having the high level. In a display period, a displayselection signal having the high level is output from each of theselection control circuit SR-R and the selection control circuit SR-L.Accordingly, the generated magnetic field can be enhanced in touchdetection, and a display drive signal is supplied from both ends of adrive electrode in a display period, and thus, the voltage of the driveelectrode can be stabilized.

<Scan Operation>

FIGS. 12 to 14 are block diagrams each showing the operation of theliquid crystal display apparatus 1 according to the first embodiment. InFIGS. 12 to 14, the operation of the liquid crystal display apparatus 1in touch detection is shown, and the operation in display is omitted.

In FIGS. 12 to 14, TL(n−2) to TL(n+7) indicate drive electrodes. Here,the drive electrodes TL(n−2) to TL(n+7) indicate drive electrodesarranged in this order from the side 2-U side of the display panel 2(FIGS. 6 and 7) to the side 2-D side. That is, the drive electrodeTL(n−2) is a drive electrode arranged closer to the side 2-U of thedisplay panel 2 than the drive electrodes TL(n−1) to TL(n+7), and thedrive electrode TL(n+7) is a drive electrode arranged closer to the side2-D of the display panel 2 than the drive electrodes TL(n−2) to TL(n+6).

The sides 2-U, 2-D of the display panel 2 correspond to the sides (sidesparallel to the row) of the pixel array LCD shown in FIG. 10, and thus,the drive electrodes TL(n−2) to TL(n+7) can be considered to be driveelectrodes arranged in this order from one side (corresponding to theside 2-U) of the pixel array LCD to the other side (corresponding to theside 2-D) of the pixel array LCD. Also in this case, the drive electrodeTL(n−2) is a drive electrode arranged closer to one side (correspondingto the side 2-U) of the pixel array LCD than the drive electrodesTL(n−1) to TL(n+7), and the drive electrode TL(n+7) is a drive electrodearranged closer to the other side (corresponding to the side 2-D) of thepixel array LCD than the drive electrodes TL(n−2) to TL(n+6).

The operation of scanning to detect whether any portion of the displaypanel 2 is touched by a pen or detect the touched position in thedisplay panel 2 will be described by using FIGS. 12 to 14. Here, theexplanation will be made for a case of scan by successively performingtouch detection from the side 2-U (one side of the pixel array LCD) ofthe display panel 2 to the side 2-D (the other side of the pixel arrayLCD). Naturally, an opposite-direction scan may be performed bysuccessively performing touch detection in the opposite direction (fromthe side 2-D to the side 2-U).

Each of FIGS. 12 to 14 is similar to the configuration shown in FIG. 11,and thus, differences will mainly be described. First, in FIGS. 12 to14, the selection control circuits SR-R, SR-L and the selection signalsTy(n−2)R to Ty(n+6)R, Ty(n−2)L to Ty(n+6)L described with reference toFIG. 11 are omitted. However, as similar to the description withreference to FIG. 11, the first switches a00 to a09 and the secondswitches b00 to b09 shown in FIGS. 12 to 14 are controlled by theselection signals Ty(n−2)R to Ty(n+6)R, Ty(n−2)L to Ty(n+6)L output fromthe selection control circuits SR-R, SR-L.

FIG. 12 shows a state in a case of the touch detection in an areacorresponding to the drive electrodes TL(n), TL(n+1) arranged close tothe side 2-U side of the display panel 2. As understood from FIG. 3, thedetection of a touch includes the magnetic field generation period TGTand the magnetic field detection period TDT. In the magnetic fieldgeneration period TGT, in order to generate a strong magnetic field inan area corresponding to the drive electrodes TL(n), TL(n+1), theselection control circuits SR-R, SR-L set the selection signals Ty(n)R,Ty(n)L assigning the drive electrodes TL(n), TL(n+1) to the high level.That is, the unit selection circuits USR(n), USL(n) corresponding to thedrive electrodes TL(n), TL(n+1) set the selection signals Ty(n)R, Ty(n)Lassigning four drive electrodes arranged so as to surround these driveelectrodes to the high level. More specifically, the touch selectionsignal Ty(n)R−2, the first touch selection signal Ty(n)L−2, and thesecond touch selection signal Ty(n)L−3 are set to the high level.Accordingly, as described with reference to FIG. 11, the first switchand the second switch are controlled as follows.

That is, by the selection signal Ty(n)R, the common terminal c in eachof the first switches a00, a01, a04, a05 is connected to the secondterminal p2. Also, by the selection signal Ty(n)L, the common terminal cin each of the second switches b00, b01 is connected to the secondterminal p2, and the common terminal c in each of the second switchesb04, b05 is connected to the third terminal p3. Accordingly, one end ofthe drive electrode TL(n−2) and one end of the drive electrode TL(n+2)are electrically connected via the first switches a00, a04. Similarly,an end of the drive electrode TL(n−1) and an end of the drive electrodeTL(n+3) are electrically connected via the first switches a01, a05.Also, the other end of the drive electrode TL(n−2) is connected to thesignal wire LL3 via the second switch b00, and the other end of thedrive electrode TL(n−1) is also connected to the signal wire LL3 via thesecond switch b01. Further, the other end of the drive electrode TL(n+2)is connected to the voltage wire VL2 via the second switch b03, and theother end of the drive electrode TL(n+3) is also connected to thevoltage wire VL2 via the second switch b04.

Accordingly, the single-winding coil CY(n) having the drive electrodesTL(n−2), TL(n+2) as a winding wire and the single-winding coil CY(n+1)having the drive electrodes TL(n−1), TL(n+3) as a winding wire areformed. In the magnetic field generation period TGT, the coil clocksignal CCLK is supplied to the signal wire LL3, and the ground voltageVss is supplied to the voltage wire VL2. As a result, each of thesecoils CY(n), CY(n+1) generates a magnetic field changing in accordancewith changes of the coil clock signal CCLK. These coils CY(n), CY(n+1)overlap in an area corresponding to the drive electrodes TL(n), TL(n+1),and thus, magnetic fields generated by respective coils are superimposedin the overlapped area in the magnetic field generation period TGT toproduce a strong magnetic field. Each of the coils CY(n), CY(n+1) has aU shape when seen in a plan view. Therefore, the wire which is connectedin the U shape is also considered to be a coil. Also, the overlapping ofthe U shapes leads to the overlapping of the coils (CY(n) and CY(n+1).

In FIG. 12, a reference character “I1” indicates a drive current flowingthrough the drive electrodes TL(n−2), TL(n+2) to be a winding wire ofthe coil CY(n) in the magnetic field generation period TGT, and areference character “I2” indicates a drive current flowing through thedrive electrodes TL(n−1), TL(n+3) to be a winding wire of the coilCY(n+1) in the magnetic field generation period TGT. In the firstembodiment, each of the coils CY(n), CY(n+1) is a single-winding coil.Thus, the length between terminals (between PTL(n−2) and PTL(n+2)) ofthe coil CY(n) can be relatively suppressed to be small. Similarly, thelength between terminals (between PTL(n−1) and PTL(n+3)) of the coilCY(n+1) can be relatively reduced to be small. As a result, even if thesheet resistance of a drive electrode is relatively high, the impedanceof each coil can be suppressed to be low, so that the drive currents I1,I2 can be increased to a high value.

By increasing the drive currents I1, I2, weakening of a magnetic fieldgenerated by each coil is suppressed, and the magnetic field generatedby each coil is superimposed in an area where the touch is detected.Therefore, in the magnetic field generation period TGT, a strongmagnetic field can be generated in the area where the touch is detected.

Depending on whether a pen approaches an area where the touch isdetected, that is, an area where coils overlap (corresponding to thedrive electrodes TL(n), TL(n+1)), the amount of charge to be charged inthe capacitative element C in the pen changes as described withreference to FIGS. 2 and 3.

In the magnetic field detection period TDT subsequent to the magneticfield generation period TGT, coils having the signal lines SL(0) toSL(p) as a winding wire are formed. If the pen internal coil L1generates a magnetic field by charges charged in the capacitativeelement C in the magnetic field generation period TGT, an inducedvoltage is generated in the coil having the signal lines as a windingwire, and is supplied to the magnetic field detection circuit SE-DET asthe sensor signals S(0) to S(p), and is detected.

In the first embodiment, a generated magnetic field can be enhanced inthe magnetic field generation period TGT, and thus, the amount of chargeto be charged in the capacitative element C in the pen can be increased,so that the accuracy of detection can be improved.

When the selection signals Ty(n)R, Ty(n)L corresponding to an area wherethe touch is detected are set to the high level, the selection controlcircuits SR-R, SR-L set all selection signals except for the selectionsignals Ty(n)R, Ty(n)L to the low level. In the description of FIG. 11as an example, each of the selection signals Ty(n−2)R, Ty(n+2)R,Ty(n+4)R, Ty(n+6)R and Ty(n−2)L, Ty(n+2)L, Ty(n+4)L, Ty(n+6)L is set tothe low level. Accordingly, the common terminal c in the first switchesexcept for the first switches a00, a01, a04, a05 is connected to thethird terminal. Also, the common terminal c in the second switchesexcept for the second switches b00, b01, b04, b05 is connected to thefourth terminal.

Because the third terminal in the first switch and the fourth terminalin the second switch are put in a floating state, drive electrodesexcept for the drive electrodes TL(n−2), TL(n−1), TL(n+2), TL(n+3) to bea winding wire of the coils CY(n), CY(n+1) are in a floating state. Inorder to clearly specify that these drive electrodes are in a floatingstate, FIG. 12 shows the common terminals c of the first switches exceptfor the first switches a00, a01, a04, a05 and the second switches exceptfor the second switches b00, b01, b04, b05 so as to be connected to nosignal wire.

FIG. 13 shows a state of the touch detection continued from FIG. 12.That is, FIG. 13 shows a state obtained when a close area to the area(corresponding to the drive electrodes TL(n), TL(n+1)) where the touchis detected as described with reference to FIG. 12 is assigned as anarea where the touch is to be detected. In this case, an area closer tothe side 2-D side of the display panel 2 than the area where the touchis detected as described with reference to FIG. 12 is the area(corresponding to the drive electrodes TL(n+2), TL(n+3)) where the touchis to be detected.

In the case of FIG. 13, the selection control circuits SR-R, SR-L setthe selection signals Ty(n+2)R, Ty(n+2)L to the high level as theselection signals that assign an area where the touch should bedetected. That is, the selection signals Ty(n+2)R, Ty(n+2)L output fromthe unit selection circuits USR(n+2), USL(n+2) are set to the highlevel. More specifically, the high-level touch selection signalTy(n+2)R−2 is output from the unit selection circuit USR(n+2), and thehigh-level first touch selection signal Ty(n+2)R−2 and the high-levelsecond touch selection signal Ty(n+2)R−3 are output from the unitselection circuit USL(n+2).

Accordingly, when the touch is detected in an area corresponding to thedrive electrodes TL(n+2), TL(n+3), the common terminal c of the firstswitches a02, a03, a06, a07 is connected to the second terminal p2, thecommon terminal c of the second switches b02, b03 is connected to thesecond terminal p2, and the common terminal c of the second switchesb06, b07 is connected to the third terminal p3 in the magnetic fieldgeneration period TGT. As a result, in the magnetic field generationperiod TGT, the coils CY(n+2), CY(n+3) overlapping with each other areformed of the drive electrodes TL(n), TL(n+1), TL(n+4), TL(n+5) in thearea where the touch is detected (corresponding to the drive electrodesTL(n+2), TL(n+3)).

The coils CY(n+2), CY(n+3) overlapping with each other are formed in thearea where the touch is detected, and these coils generate magneticfields in accordance with changes of the coil clock signal CCLK.Therefore, as similar to the description with reference to FIG. 12, astrong magnetic field can be generated in an area where the touch isdetected in the magnetic field generation period TGT.

Also in the case of FIG. 13, as similar to FIG. 12, coils are formed ofsignal lines in the magnetic field detection period TDT subsequent tothe magnetic field generation period TGT, and signals in the formedcoils are supplied to the magnetic field detection circuit SE-DET as thesensor signals S(0) to S(p), so that the touch is detected.

As similar to FIG. 12, note that the selection control circuits SR-R,SR-L set the selection signals except for the selection signalsTy(n+2)R, Ty(n+2)L that assign the area where the touch should bedetected to the low level. Accordingly, drive electrodes except for thedrive electrodes TL(n), TL(n+1), TL(n+4), TL(n+5) to be a winding wireof the coils are in a floating state. In order to clearly specify thatthese drive electrodes are in a floating state, FIG. 12 also shows thecommon terminals c of the first switches except for the first switchesa02, a03, a06, a07 and the second switches except for the secondswitches b02, b03, b06, b07 so as to be connected to no signal wire assimilar to FIG. 12.

FIG. 14 shows a state of the touch detection continued from FIG. 13.That is, FIG. 14 shows a state obtained when a close area to the area(corresponding to the drive electrodes TL(n+2), TL(n+3)) where the touchis detected as described with reference to FIG. 13 is assigned as anarea where the touch is to be detected. In this case, an area closer tothe side 2-D side of the display panel 2 than the area where the touchis detected as described with reference to FIG. 13 is the area(corresponding to the drive electrodes TL(n+4), TL(n+5)) where the touchis to be detected.

In the case of FIG. 14, the selection control circuits SR-R, SR-L setthe selection signals Ty(n+4)R, Ty(n+4)L to the high level as theselection signals that assign an area where the touch should bedetected. That is, the selection signals Ty(n+4)R, Ty(n+4)L output fromthe unit selection circuits USR(n+4), USL(n+4) are set to the highlevel. More specifically, the high-level touch selection signalTy(n+4)R−2 is output from the unit selection circuit USR(n+4), and thehigh-level first touch selection signal Ty(n+4)R−2 and the high-levelsecond touch selection signal Ty(n+4)R−3 are output from the unitselection circuit USL(n+4).

Accordingly, when the touch is detected in an area corresponding to thedrive electrodes TL(n+4), TL(n+5), the common terminal c of the firstswitches a04, a05, a08, a09 is connected to the second terminal p2, thecommon terminal c of the second switches b04, b05 is connected to thesecond terminal p2, and the common terminal c of the second switchesb08, b09 is connected to the third terminal p3 in the magnetic fieldgeneration period TGT. As a result, in the magnetic field generationperiod TGT, the coils CY(n+4), CY(n+5) overlapping with each other areformed of the drive electrodes TL(n+2), TL(n+3), TL(n+6), TL(n+7) in thearea where the touch is detected (corresponding to the drive electrodesTL(n+4), TL(n+5)).

The coils CY(n+4), CY(n+5) overlapping with each other are formed in thearea where the touch is detected, and these coils generate magneticfields in accordance with changes of the coil clock signal CCLK.Therefore, as similar to the description with reference to FIG. 12, astrong magnetic field can be generated in an area where the touch isdetected in the magnetic field generation period TGT.

Also in the case of FIG. 14, as similar to FIG. 12, coils are formed ofsignal lines in the magnetic field detection period TDT subsequent tothe magnetic field generation period TGT, and signals in the formedcoils are supplied to the magnetic field detection circuit SE-DET as thesensor signals S(0) to S(p), so that the touch is detected.

As similar to FIG. 12, note that the selection control circuits SR-R,SR-L set the selection signals except for the selection signalsTy(n+4)R, Ty(n+4)L that assign the area where the touch should bedetected to the low level. Accordingly, drive electrodes except for thedrive electrodes TL(n+2), TL(n+3), TL(n+6), TL(n+7) to be a winding wireof the coils are in a floating state. In order to clearly specify thatthese drive electrodes are in a floating state, FIG. 14 also shows thecommon terminals c of the first switches except for the first switchesa04, a05, a08, a09 and the second switches except for the secondswitches b04, b05, b08, b09 so as to be connected to no signal wire assimilar to FIG. 13.

By performing the touch detection successively from the side 2-U towardthe side 2-D in the display panel 2 as described above, a scan operationfrom the side 2-U toward the side 2-D can be performed. By performing ascan operation, whether any portion of the display panel 2 is touched orthe touched position of the display panel 2 can be scanned.

In the first embodiment, in a scan operation, the drive electrodes aresuccessively assigned from the drive electrodes TL(n−2) to TL(n+7)arranged between the side 2-U and the side 2-D of the display panel 2 byselection signals output from the selection control circuits SR-R, SR-L,and two single-winding coils are formed of the assigned driveelectrodes. A strong magnetic field is formed in an area where the twoformed coils overlap, and the touch detection is performed in theoverlapped area. Accordingly, the touch detection can be successivelyperformed so as to scan the display panel 2.

From a different viewpoint, the touch detection can be considered to beperformed by two coils, each of which is a single-winding wire, whilethe two coils are successively shifted from the side 2-U toward the side2-D in the display panel 2 in accordance with selection signals from theselection control circuits SR-R, SR-L. In this case, the value of theshifted area in the two coils, each of which is a single-winding wire,serving as one unit, is substantially the same as the value of the areawhere the touch is detected. That is, in the first embodiment, the valueof the shifted area and the value of the area where the touch isdetected correspond to two close (adjacent) drive electrodes (forexample, TL(n) and TL(n+1)). If two drive electrodes forming asingle-winding coil is considered to be a bundle, the scan operation isachieved by performing the touch detection while two bundles (a firstbundle and a second bundle) are shifted by two bundles in accordancewith selection signals from the selection control circuits SR-R, SR-L.

In the first embodiment, in the magnetic field generation period TGT,two coils are formed by using drive electrodes arranged so as to beclose to each other. In the description of FIG. 11 as an example, when astrong magnetic field is generated in an area corresponding to the driveelectrodes TL(n), TL(n+1), the drive electrode TL(n−2) and the driveelectrode TL(n−1) arranged close to each other are used as one windingwire of each of two coils. Also, the drive electrode TL(n+2) and thedrive electrode TL(n+3) arranged close to each other are used as theother winding wire of each of the two coils. Each width of the driveelectrodes, that is, each length thereof in a direction perpendicular tothe extending direction of the drive electrodes are substantially thesame. Thus, in the first embodiment, the width of the area where twocoils overlap (area where the touch is detected) is substantially thesame as the total width of drive electrodes used as one (or the other)winding wire of two coils.

<Switching Adjustment Circuits SCX-U, SCX-D and Selection ControlCircuit SRX-D>

FIG. 16 is a block diagram showing the configuration of the switchingadjustment circuit SCX-D and the selection control circuit SRX-D in theliquid crystal display apparatus 1 according to the first embodiment.FIG. 17 is a block diagram showing the configuration of the switchingadjustment circuit SCX-U in the liquid crystal display apparatus 1according to the first embodiment.

FIG. 16 shows a portion of the switching adjustment circuit SCX-Dcorresponding to the signal lines SL(n−6) to SL(n+9) shown in FIG. 8 anda portion of the selection control circuit SRX-D corresponding to thesignal lines SL(n−6) to SL(n+9). Reference characters D(−6) to D(+9)shown in FIG. 8 are connected to reference characters D(−6) to D(+9)shown in FIG. 16, respectively. Similarly, FIG. 17 shows a portion ofthe switching adjustment circuit SCX-U corresponding to the signal linesSL(n−6) to SL(n+9) shown in FIG. 8. Reference characters U(−6) to U(+9)shown in FIG. 8 are connected to reference characters U(−6) to U(+9)shown in FIG. 17, respectively.

<<Coil Formed of Signal Lines>>

Before the description for the switching adjustment circuits SCX-D,SCX-U and the selection control circuit SRX-D, a coil (detection coil)formed of signal lines in the first embodiment will be described.

Although not specifically limited, a plurality of double-winding coilsare formed of the signal lines SL(0) to SL(P) in touch detection in thefirst embodiment. Here, coils CX(n−2) to CX(n+1) formed in touchdetection from the signal lines SL(n−6) to SL(n+9) shown in FIG. 8 aredescribed as an example.

FIG. 18 is a schematic plan view of coils having the signal linesSL(n−6) to SL(n−3), SL(n) to SL(n+3), and SL(n+6) to SL(n+9) as windingwires. In the touch detection, the coils CX(n−2) to CX(n+1) are formedof these signal lines and signal wires connecting ends of these signallines.

As described later with reference to FIGS. 16 and 17, ends of thefollowing signal lines are electrically connected via signal wires inthe touch detection.

One end of the signal line SL(n−5) is electrically connected to one endof the signal line SL(n+2) via a signal wire 6511. The other ends of thesignal lines SL(n−6), SL(n−5) are connected to the other ends of thesignal lines SL(n+2), SL(n+3) via signal wires 6521, 6531, respectively.Further, the ground voltage Vss is supplied to one end of the signalline SL(n+3), and one end of the signal line SL(n−6) is connected to anoutput terminal Xp1(n 1). Accordingly, in the touch detection, thesignal lines SL(n−6), SL(n−5), SL(n+2), SL(n+3) are connected in seriesbetween the ground voltage Vss and the output terminal Xp1(n−1). Thesignal lines SL(n−6) to SL(n+9) extend in parallel with each other.Thus, in the touch detection, the coil CX(n−1) having the signal linesSL(n−6), SL(n−5), SL(n+2), SL(n+3) as winding wires is formed.

Also, one end of the signal line SL(n+1) is electrically connected toone end of the signal line SL(n+8) via a signal wire 6512. The otherends of the signal lines SL(n), SL(n+1) are connected to the other endsof the signal lines SL(n+8), SL(n+9) via signal wires 6522, 6532,respectively. Further, the ground voltage Vss is supplied to one end ofthe signal line SL(n+9), and one end of the signal line SL(n) isconnected to an output terminal Xp1(n). Accordingly, in the touchdetection, the signal lines SL(n−6), SL(n−5), SL(n+2), SL(n+3) areconnected in series between the ground voltage Vss and the outputterminal Xp(n), so that the coil CX(n) having the signal lines SL(n),SL(n+1), SL(n+8), SL(n+9) as winding wires is formed in the touchdetection.

Similarly, the coil CX(n+1) is formed between an output terminalXp1(n+1) and the ground voltage Vss by making the connection between thesignal lines SL(n+6), SL(n+7) and signal lines not shown via signalwires 6513, 6523, 6533. Further, the coil CX(n−2) is formed by makingthe connection between the signal lines SL(n−4), SL(n−3) and signallines not shown via signal wires 6510, 6520, 6530.

The coils f having the signal lines SL(0) to SL(p) as winding wires intouch detection extend in an extending direction of the signal lines. Onthe other hand, coils shown in FIGS. 11 to 14, that is, coils havingdrive electrodes as winding wires extend in the extending direction ofthe drive electrodes. Thus, coils having signal lines as winding wiresand coils having drive electrodes as winding wires are orthogonal toeach other. In the description of the coils CY(n) to CY(n+5) shown inFIG. 15 and the coils CX(n−2) to CX(n+1) shown in FIG. 18 as an example,the coils CY(n) to CY(n+5) and the coils CX(n−2) to CX(n+1) areorthogonal to each other while they are electrically insulated from eachother.

In the first embodiment, the coils CX(n−2) to CX(n+1) formed in touchdetection are formed so as to overlap with each other. In thedescription of the coils CX(n), CX(n−1) as an example, the signal linesSL(n+2), SL(n+3) serving as a winding wire of the coil CX(n−1) arearranged inside the coil CX(n). Similarly, the signal lines SL(n),SL(n+1) serving as a winding wire of the coil CX(n) are arranged insidethe coil CX(n−1). In this manner, in the touch detection, occurrence ofan area where the accuracy of detection of a magnetic field is degradedcan be prevented by making the coils overlap.

<<Configuration of the Switching Adjustment Circuit SCX-D and theSelection Control Circuit SRX-D>>

Next, the configuration of the switching adjustment circuit SCX-D andthe selection control circuit SRX-D will be described with reference toFIGS. 16 and 8. FIG. 16 shows the configuration of a portioncorresponding to the signal lines SL(n−6) to SL(n+9) and a schematicconfiguration of the signal line selector 3.

In the display period, an image signal is supplied to each of terminalsSP from the display control device 4 (FIG. 6) in time-division mode. InFIG. 14, in order to avoid the complexity of the drawing, note that areference character SP is attached to only the terminal arrangedrightmost and the terminal arranged leftmost.

The signal line selector 3 includes a plurality of switchesswitch-controlled by the selection signals SEL1, SEL2 to supply an imagesignal, which is supplied to the terminal SP, to an appropriate signalline. While switches in the signal line selector 3 selectively connectthe terminals SP and signal lines in a display period, they connect allsignal lines and the terminals SP substantially at the same time in atouch detection period. In order to show the change between the displayperiod and the touch detection period in the connection of signal linesand the terminals SP, FIG. 16 shows a schematic switch SW11 (referencecharacter SW11 is attached to only the rightmost switch and the leftmostswitch) as a switch included in the signal line selector 3. That is, theswitch SW11 shown in FIG. 16 is illustrated to show that the signallines SL(0) to SL(p) and the terminals SP are connected in a touchdetection period.

The switching adjustment circuit SCX-D includes third switches c00 toc05 switch-controlled by the magnetic-field enable signal SC_EN, fourthswitches d00 to d02 switch-controlled by selection signals X-Out(n−1) toX-Out(n+1) from the selection control circuit SRX-D, and signal wires6510 to 6513.

In the assignment to the touch detection, the control circuit D-CNT(FIG. 6) sets the magnetic-field enable signal SC_EN to the high level.In the non-assignment to the touch detection or in the display period,the control circuit D-CNT sets the magnetic-field enable signal SC_EN tothe low level. The third switches c00 to c05 are turned on when themagnetic-field enable signal SC_EN is set to the high level. On theother hand, when the magnetic-field enable signal SC_EN is set to thelow level, the third switches c00 to c05 are turned off. Also, theswitch SW11 in the signal line selector 3 is turned on in a touchdetection period, and thus, the terminals SP and the signal linesSL(n−6) to SL(n+9) are electrically connected.

Accordingly, in the touch detection period, one end of the signal lineSL(n−5) is connected to one end of the signal line SL(n+2) via the thirdswitch c00 and the signal wire 6511, and one end of the signal lineSL(n+1) is connected to one end of the signal line SL(n+8) via the thirdswitch c02 and the signal wire 6512. Also, the signal line SL(n−4) isconnected to a signal line not shown via the signal wire 6510 and athird switch not show, and the signal line SL(n+7) is connected to asignal line not shown via the third switch c04 and the signal wire 6513.

In the touch detection period, one end of each of the signal linesSL(n−3), SL(n+9) is connected to the voltage wire VL2 via the thirdswitches c01, c05 respectively. In the touch detection period, forexample, the ground voltage Vss is supplied to the voltage wire VL2.Also, in the touch detection period, the fourth switches d00 to d02 areturned on in accordance with the selection signals X-Out(n−1) toX-Out(n+1) from the selection control circuit SRX-D.

When the touch detection is started, the control circuit D-CNT shown inFIG. 6 sets the control signals X-CNT, Y-CNT to, for example, the highlevel. The control signal X-CNT becomes at the high level, so that theselection control circuit SRX-D performs a coil selection operation insynchronization with changes of the clock signal CLK. For example, theselection control circuit SRX-D sets the selection signals X-Out(0) toX-Out(p) to the high level in this order in synchronization with changesof the clock signal CLK. The selection control circuit SRX-D includesinput terminals XIO(0) to XIO(p) corresponding to the coils CX(0) toCX(p), respectively. When the selection signals X-Out(0) to X-Out(p)successively become at the high level, the fourth switches aresuccessively brought into conduction so that signals from the coilsCX(0) to CX(p) are supplied to the input terminals XIO(0) to XIO(p). Theselection control circuit SRX-D outputs supplied signals as the sensesignals S(0) to S(p) in the magnetic field detection period TDT. Notethat FIG. 16 shows only input terminals XIO(n−1) to XIO(n+1) connectedto respective output terminals Xp1(n−1) to Xp1(n+1) of the coils CX(n−1)to CX(n+1) and selection signals X-Out(n−1) to X-Out(n+1) correspondingto these input terminals.

In FIG. 16, note that a reference character DDIC shown by a broken lineindicates a semiconductor device for drive. The semiconductor device fordrive DDIC is arranged so as to cover the switching adjustment circuitSCX-D and the selection control circuit SRX-D described above, and anexternal terminal of the semiconductor device for drive DDIC isconnected to the terminal SP. From the external terminal of thesemiconductor device for drive DDIC connected to the terminal SP, animage signal is supplied to the terminal SP in a display period. In atouch detection period, the external terminal of the semiconductordevice for drive DDIC is put into a high-impedance state.

Note that the output terminals Xp1(0) to Xp1(p) of the coils CX(0) toCX(p) may be connected to the input terminals XIO(0) to XIO(p) of theselection control circuit SRX-D, respectively, without providing thefourth switches. In this manner, signals from the coils CX(0) to CX(p)can be output from the selection control circuit SRX-D as the sensesignals S(0) to S(p), respectively.

<<Configuration of the Switching Adjustment Circuit SCX-U>>

FIG. 17 is a circuit diagram showing the configuration of the switchingadjustment circuit SCX-U. FIG. 17 shows a portion of the switchingadjustment circuit SCX-U corresponding to the signal lines SL(n−6) toSL(n+9). The switching adjustment circuit SCX-U includes fifth switchese00 to e05 switch-controlled by the magnetic-field enable signal SC_ENand signal wires 6520 to 6523, 6530 to 6533. To the fifth switches e00to e05, the high-level magnetic-field enable signal SC_EN is supplied intouch detection, and therefore, these switches are turned on. On theother hand, in no assignment to the touch detection and in the displayperiod, the fifth switches e00 to e05 are turned off.

In touch detection, in the switching adjustment circuit SCX-U, the otherend of the signal line SL(n−6) is connected to the other end of thesignal line SL(n+2) via the fifth switch e00 and the signal wire 6521,and the other end of the signal line SL(n−5) is connected to the otherend of the signal line SL(n+3) via the fifth switch e01 and the signalwire 6531. At this time, in the switching adjustment circuit SCX-U, theother end of the signal line SL(n) is connected to the other end of thesignal line SL(n+8) via the fifth switch e02 and the signal wire 6522,and the other end of the signal line SL(n+1) is connected to the otherend of the signal line SL(n+9) via the fifth switch e03 and the signalwire 6532. Also at this time, the signal line SL(n−4) is connected to asignal line not shown via a fifth switch not shown and the signal wire6520, and the signal line SL(n−3) is connected to a signal line notshown via a fifth switch not shown and the signal wire 6520. Further,the signal line SL(n+6) is connected to a signal line not shown via thefifth switch e04 and the signal wire 6523, and the signal line SL(n+7)is connected to a signal line not shown via the fifth switch e05 and thesignal wire 6533.

<<The Switching Adjustment Circuits SCX-D, SCX-U and the SelectionControl Circuit SRX-D>>

When the touch detection is assigned, in the switching adjustmentcircuit SCX-D, the signal line SL(n−5) and the signal line SL(n+2) areconnected, the signal line SL(n+1) and the signal line SL(n+8) areconnected, and the signal lines SL(n+3), SL(n+9) are connected to thevoltage wire VL2. Also when the touch detection is assigned, in theswitching adjustment circuit SCX-U, the signal line SL(n−6) and thesignal line SL(n+2) are connected, the signal line SL(n−5) and thesignal line SL(n+3) are connected, the signal lines SL(n) and the signalSL(n+8) are connected, and the signal lines SL(n+1) and the signalSL(n+9) are connected. Accordingly, when the touch detection isassigned, the signal lines SL(n−6), SL(n−5), SL(n+2), SL(n+3) arrangedin parallel with each other are connected in series in the display panel2, so that the coil X(n−1) having these signal lines as a winding wireis formed. Similarly, when the magnetic field touch detection isassigned, the signal lines SL(n), SL(n+1), SL(n+8), SL(n+9) areconnected in series, so that the coil X(n) having these signal lines asa winding wire is formed.

At this time, to one end of each of the coils X(n−1), X(n), the voltagewire VL2 is connected, so that the ground voltage Vss is suppliedthereto. If the coil X(n−1) or/and the coil X(n) are selected by theselection control circuit SRX-D, the selection signals X-Out(n−1) or/andX-Out(n) are set to the high level. Accordingly, the other ends of theselected coils X(n−1) or/and X(n) are connected to the input terminalsXIO(n−1) or/and XIO(n) of the selection control circuit SRX-D via thefourth switches d00 or/and d01.

In the magnetic field generation period TGT of touch detection, asdescribed with reference to FIGS. 11 to 14, a strong magnetic field isgenerated in an area where the touch should be detected by coils (forexample, the coils CY(n), CY(n+1)) having drive electrodes as windingwires. At this time, the amount of charge to be charged in thecapacitative element C in the pen is determined depending on whether thepen approaches the area where the touch is to be detected or not.

In the magnetic field detection period TDT subsequent to the magneticfield generation period TGT, the selection control circuit SRX-D setsonly the selection signal X-Out(n−1) or X-Out(n) corresponding to thecoil X(n−1) or X(n) to be selected to the high level, and the selectionsignal corresponding to the coil X(n−1) or X(n) to be not selected tothe low level. Accordingly, the output terminal of the selected coilX(n−1) or X(n) is connected to the input terminal of the selectioncontrol circuit SRX-D, and the output terminal of the non-selected coilis not connected to the input terminal of the selection control circuitSRX-D.

In touch detection, if a pen exists in vicinity of the selected coil inan area where the touch should be detected, the pen internal coil L1generates a magnetic field by charges charged in the capacitativeelement C inside the pen, and an induced voltage is generated in theselected coil by the generated magnetic field. As a result, signalchange occurs in the output terminal of the selected coil. The signalchange is transferred to the input terminal of the selection controlcircuit SRX-D, and is output from the selection control circuit SRX-D asthe sense signal S(n). On the other hand, in touch detection, if a pendoes not exist in an area where the touch should be detected or invicinity of the selected coil, no signal change occurs in the outputterminal of the selected coil, and this is output as the sense signalS(n).

Meanwhile, in a display period, the third switches c00 to c05, thefourth switches d00 to d02, and the fifth switches e00 to e05 are turnedoff. Accordingly, the signal lines SL(n−6) to SL(n+9) are electricallyinsulated from each other. In a display period, an image signal issupplied from the display control device 4 to the terminal SP, and thesignal lines SL(n−6) to SL(n+9) can transfer the image signal.

<Structure of the Signal Wire>

In the first embodiment, the switching circuit DSC and the selectiondrive circuit SDC are arranged outside the display panel 2 (pixel arrayLCD). That is, the signal wires LL1, LL2 included in the switchingcircuit DSC and the selection drive circuit SDC are formed of wiresarranged outside the display panel 2. Here, the structure of the signalwire using wires arranged outside the display panel 2 will be describedwhile exemplifying the signal wire LL1 shown in FIG. 11. FIG. 19 is across-sectional view showing a cross section of B1-B1′ and a crosssection of B2-B2′ in FIG. 11. Note that the structure of the crosssection in the display panel 2 is shown in FIG. 9, and thus, thedescription thereof is omitted.

In FIG. 19, a reference character [603] indicates a second wiring layer603, and a reference character [605] indicates a third wiring layer 605.The drive electrodes TL(0) to TL(p) and the auxiliary electrode SM areformed of wires arranged in the third wiring layer. The drive electrodesTL(0) to TL(p) and the auxiliary electrode SM formed in the displaypanel 2 extend to the switching circuit DSC and the selection drivecircuit SDC arranged outside the display panel 2 although notspecifically limited. FIG. 19 shows the drive electrodes TL(n+1),TL(n+8) extending to the switching circuit DSC and the auxiliaryelectrode SM arranged on these drive electrodes. In order to clearlyshow that the drive electrodes TL(n), TL(n−2) and the auxiliaryelectrode SM are formed of wires of the third wiring layer 605, FIG. 19shows these electrodes as reference characters TL(n)[605], TL(n−2), andSM[605] in.

In the first embodiment, signal wires included in the switching circuitDSC and the selection drive circuit SDC are formed of wires in thesecond wiring layer. That is, the signal wire LL1 is formed of the wireLL1 [603] formed in the second wiring layer 603. The wire LL1[603] isconnected to the drive electrode TL(n)[605] and the auxiliary electrodeSM[605] via the first switch a02, and further connected to the driveelectrode TL(n−2)[605] and the auxiliary electrode SM [605] via thefirst switch a00. Note that the switching circuit DSC and the selectiondrive circuit SDC are outside the display panel 2, and thus, the liquidcrystal layer 607 is not formed on the insulating layer 606 shown inFIG. 19.

In the first embodiment, wires of the second wiring layer 603 are usedas the signal wires LL1, LL2 that connect drive electrodes in order toform a coil. That is, wires of the same wiring layer as the signal linesSL(0) to SL(p) are used as the signal wires LL1, LL2. Also, the driveelectrodes and the auxiliary electrode are used as winding wires ofcoils. Thus, coils can be formed without increasing the number of thewiring layers, so that increase in a piece can be suppressed.

When the signal lines SL(0) to SL(p) are formed, wires parallel to thesignal lines SL(0) to SL(p) may be also formed outside the display panel2, and the wires formed outside the display panel 2 are used as thesignal wires LL1, LL2 described above.

FIG. 20 is a plan view specifically showing an area PP1 surrounded by abroken line in FIG. 11. In FIG. 20, reference characters R, G, and Bindicate pixels of the three primary colors, and reference charactersTL(n−1) to TL(n+1) indicate drive electrodes. Also, a referencecharacter SM indicates an auxiliary electrode and is electricallyconnected to drive electrodes. Further, in FIG. 20, reference charactersGL(n−2) to GL(n+3) indicate scanning lines.

As shown in FIG. 20, a plurality of auxiliary electrodes SM areconnected to one drive electrode TL(n). For example, several tens ofauxiliary electrodes SM extend in parallel with the drive electrodeTL(n) and are connected to the drive electrode TL(n). Accordingly, theresistance of a coil can be reduced when the coil is formed of the driveelectrodes and auxiliary electrodes SM.

An example in which wires in the second wiring layer 603 are used as thesignal wires LL1, LL2 has been described. However, the presentembodiment is not limited to such an example. For example, wires in thefirst wiring layer 601 may be used as signal wires, or wires in thethird wiring layer 605 may be used as signal wires.

In the first embodiment, the switching adjustment circuits SCX-U, SCX-Dare arranged outside the display panel 2 (pixel array LCD). That is,signal wires included in the switching adjustment circuits SCX-U, SCX-Dare formed of wires arranged outside the display panel 2. In thedescription of the example shown in FIGS. 16 and 17, the signal wires6510 to 6513, 6520 to 6523, and 6530 to 6533 are formed of wiresarranged outside the display panel 2. Here, the structure of a signalwire using wires arranged outside the display panel 2 will be describedwhile exemplifying the signal wire 6512 included in the switchingadjustment circuit SCX-D. FIG. 21 is a cross-sectional view showing across section of B1-B1′ and a cross section of B2-B2′ in FIG. 16. Notethat the structure of the cross section in the display panel 2 is shownin FIG. 9, and thus, the description thereof is omitted.

In FIG. 21, a reference character [603] indicates a wire of a secondwiring layer, and a reference character [605] indicates a wire of athird wiring layer. The signal lines SL(0) to SL(p) are formed of wiresformed in the second wiring layer. Signal lines formed in the displaypanel 2 are connected to wires of the second wiring layer in theswitching adjustment circuits SCX-U, SCX-D. In FIG. 21, referencecharacters SL(n+1)[603] to SL(n+3)[603] and SL(n+8)[603] indicate wiresof the second wiring layer to which the signal lines SL(n+1) to SL(n+3)and SL(n+8) are connected in the switching adjustment circuit SCX-D. Thesignal wire 6512 shown in FIG. 16 is formed of the wire 6512[605] formedin the third wiring layer 605. The wire 6512[605] is connected to thewires SL(n+1)[603] and SL(n+8)[603] by an interlayer wire SLC. In thiscase, the wire 6512[605] includes a wire corresponding to the auxiliaryelectrode SM and a wire corresponding to the drive electrode. Note thatthe switching adjustment circuits SCX-U, SCX-D are outside the displaypanel 2, and thus, the liquid crystal layer 607 is not formed on theinsulating layer 606 shown in FIG. 21.

In the first embodiment, wires in the third wiring layer 605 are used assignal wires that connect signal lines in order to form a coil. That is,wires of the same wiring layer as the drive electrode TL and theauxiliary electrode SM are used as the signal wires 6510 to 6513, 6520to 6523, and 6530 to 6533. Also, signal lines are used as winding wiresof coils. Thus, coils can be formed without increasing the number of thewiring layers, so that increase in a price can be suppressed. Forexample, when the drive electrode TL and the auxiliary electrode areformed in an active area of the display panel 2, wires may also beformed outside the display panel 2 (outside the active area) to usewires formed outside the display panel 2 as the above-described signalwires.

Also, when the drive electrode TL and the auxiliary electrode areformed, wires parallel to the drive electrode TL and the auxiliaryelectrode may be also formed outside the display panel 2 to use wiresformed outside the display panel 2 as the above-described signal wires.In this case, a portion that is not connected to a signal wire may becut. Wires that are not required because of being cut may be left or beremoved.

FIG. 22 is a plan view specifically showing an area PP2 surrounded by analternate long and short dash line in FIG. 18 in detail. In FIG. 22,reference characters R, G, and B indicate pixels of the three primarycolors, and a reference character TL indicates a drive electrode. Also,reference characters SL(n+6)1(G) to SL(n+8)0(G), SL(n+6)1(B) toSL(n+8)0(B), and SL(n+7)0(R) to SL(n+8)0(R) indicate signal lines.

In the first embodiment, as the signal line SL(n+8) shown in FIG. 8, aplurality of signal lines of the signal lines SL(n+6)1(G) toSL(n+8)0(G), SL(n+6)1(B) to SL(n+8)0(B), and SL(n+7)0(R) to SL(n+8)0(R)shown in FIG. 22 are used. That is, when a coil is formed of signallines, a plurality of signal lines are connected to each other so as toserve as one signal line and are used as a winding wire of the coil.Accordingly, the resistance of the coil can be reduced. In this case, itis desired to, for example, electrically connect several tens of signallines to each other to use as a winding wire of a coil.

In FIGS. 15 to 17, a case when the number of windings of a coil formedof signal lines is 2 has been described. However, the present embodimentis not limited to such a case. The number of windings of a coil can beincreased or decreased by changing the number of connections of signallines and signal wires in the switching adjustment circuits SCX-U,SCX-D. Also by changing connections of signal lines and signal wires,any signal line can be used as a winding wire of the coil. Further, bychanging connections in the switching adjustment circuits SCX-U, SCX-D,a degree of overlap between the coils close to each other can bechanged. That is, coils used in a touch detection period can be adjustedby an adjustment unit.

An example in which wires in the third wiring layer 605 are used assignal wires have been described. However, the present embodiment is notlimited to such an example. For example, wires in the first wiring layermay be used as the signal wires 6510 to 6513, 6520 to 6523, and 6530 to6533. In this case, when the scanning lines GL(0) to GL(p) are formed,wires to be used as the signal wires 6510 to 6513, 6520 to 6523, and6530 to 6533 are formed. Also in this case, increase in a price can besuppressed.

Second Embodiment

FIGS. 23 and 24 are block diagrams showing the configuration of theliquid crystal display apparatus 1 according to the second embodiment.FIG. 24 continues from FIG. 23. That is, a portion indicated by areference character DD in FIG. 23 continues to a portion indicated by areference character DD in FIG. 24. As similar to FIG. 11, FIGS. 23 and24 show drive electrodes TL(0) to TL(p) (first drive electrodes), aswitching circuit DSC1, a selection drive electrode SDC1, and selectioncontrol circuits SR1-R, SR1-L. In FIGS. 23 and 24, TL(du1) to TL(du3)and TL(dd1) to TL(dd3) are drive electrodes for magnetic fieldgeneration (hereinafter, each of which is also called magnetic-fielddrive electrode (second drive electrode)) although not specificallylimited.

In the first embodiment, two coils each of which is a single-windingwire are formed in the magnetic field generation period TGT, and amagnetic field is generated while two coils are set to be a unit. In thesecond embodiment, by contrast, three coils each of which is asingle-winding wire are formed in the magnetic field generation periodTGT, and a magnetic field is generated while three coils are set to be aunit. Also, in the first embodiment, an area where areas of two coilsoverlap each other is an area corresponding to two drive electrodes.However, in the second embodiment, an area where areas of three coilsoverlap one another is set as an area corresponding to one driveelectrode.

Further, in the scan operation in the first embodiment, coils areshifted by each two coils to be a unit, and the shift amount correspondsto two coils. On the other hand, in the second embodiment, while coilsare shifted by each three coils to be a unit, the shift amountcorresponds to one coil.

<Drive Electrode for Magnetic Field>

In the second embodiment, the drive electrodes TL(0) to TL(p) arearranged from the side 2-U side toward the side 2-D side of the displaypanel 2 (pixel array LCD) in this order although not specificallylimited. That is, in the active area of the display panel 2, the driveelectrodes TL(0) to TL(P) are arranged. In contrast, the driveelectrodes for magnetic field TL(du1) to TL(du3) are arranged along theside 2-U of the display panel 2 (pixel array LCD), but are arrangedoutside the active area of the display panel 2. Similarly, the driveelectrodes for magnetic field TL(dd1) to TL(dd3) are arranged along theside 2-D of the display panel 2 (pixel array LCD), but are arrangedoutside the active area of the display panel 2.

Each of the drive electrodes for magnetic field TL(du1) to TL(du3) isarranged to extend in parallel with the drive electrodes TL(0) to TL(p),and is arranged so as to be distant away from the side 2-U of thedisplay panel 2 in the order of the drive electrodes for magnetic fieldTL(du3) to TL(du1). Although not specifically limited, a width d1 of thedrive electrode for magnetic field TL(du1) is made narrower than a widthd2 of the drive electrode for magnetic field TL(du2), and the width d2of the drive electrode for magnetic field TL(du2) is made narrower thana width d3 of the drive electrode for magnetic field TL(du3). Further,the width d3 of the drive electrode for magnetic field TL(du3) is madenarrower than a width d4 of each of the drive electrodes TL(0) to TL(p).

Similarly, each of the drive electrodes for magnetic field TL(dd1) toTL(dd3) is arranged to extend in parallel with the drive electrodesTL(0) to TL(P), and is arranged so as to be distant away from the side2-D of the display panel 2 in the order of the drive electrodes formagnetic field TL(dd3) to TL(dd1). Although not specifically limited, awidth d5 of the drive electrode for magnetic field TL(dd1) is madenarrower than a width d6 of the drive electrode for magnetic fieldTL(dd2), and the width d6 of the drive electrode for magnetic fieldTL(dd2) is made narrower than a width d7 of the drive electrode formagnetic field TL(dd3). Further, the width d7 of the drive electrode formagnetic field TL(dd3) is made narrower than the width d4 of each of thedrive electrodes TL(0) to TL(p).

In the description by associating with the pixel array LCD, each of thedrive electrodes for magnetic field TL(du1) to TL(du3) is arranged alonga side (corresponding to the side 2-U of the display panel 2) parallelto the row of the pixel array LCD, and each of them is parallel to therow of the pixel array LCD. Also, the drive electrodes for magneticfield TL(du3) to TL(du1) are arranged so as to be distant away from aside (corresponding to the side 2-U) of the pixel array LCD in thisorder. Similarly, each of the drive electrodes for magnetic fieldTL(dd1) to TL(dd3) is arranged along a side (corresponding to the side2-D of the display panel 2) parallel to the row of the pixel array LCD,and each of them is parallel to the row of the pixel array LCD. Also,the drive electrodes for magnetic field TL(dd3) to TL(dd1) are arrangedso as to be distant away from a side (corresponding to the side 2-D) ofthe pixel array LCD in this order.

The drive electrodes for magnetic field TL(du1) to TL(du3) and TL(dd1)to TL(dd3) are formed outside the active area of the display panel 2,and thus, does not function in the display. That is, the display is notaffected regardless of either the supply or non-supply of a displaydrive signal to the drive electrodes for magnetic field TL(du1) toTL(du3) and TL(dd1) to TL(dd3) in the display. The drive electrodes formagnetic field TL(du1) to TL(du3) and TL(dd1) to TL(dd3) are combinedwith drive electrodes in the magnetic field generation period TGT. Thatis, in the magnetic field generation period TGT, coils are formed ofdrive electrodes and drive electrodes for magnetic field close to theside 2-U or the side 2-D of the display panel 2 (pixel array LCD). Inthis case, electrodes which are arranged outside the display panel 2 andwhich are combined with drive electrodes in a magnetic field generationperiod to form a coil can be considered to be drive electrodes formagnetic field.

<The Selection Control Circuits SR1-R, SR1-L>

The selection control circuits SR1-R, SR1-L have a configuration similarto that of the selection control circuits SR-R, SR-L described in thefirst embodiment. That is, each of the selection control circuits SR1-R,SR1-L has a shift register, and includes a plurality of unit selectioncircuits corresponding to respective steps of the shift register. Theshift register performs a shift operation in synchronization withchanges of the clock signal CLK by the setting of the magnetic-fieldenable signal SC_EN to the high level and the setting of the controlsignal Y-CNT to the high level so that the operation of touch detectionis assigned. By the shift operation, selection signals Ty(0)R to Ty(p)Rand Ty(0)L to Ty(p)L that are successively set to the high level areoutput from the unit selection circuits corresponding to respectivesteps of the shift register. As similar to the first embodiment, notethat the selection control circuit SR1-R and the selection controlcircuit SR1-L operate in synchronization with each other. That is, forexample, when the selection signal Ty(n)R from the selection controlcircuit SR1-R changes to the high level, the selection signal Ty(n)Lfrom the selection control circuit SR1-L also changes to the high level.

The selection signals Ty(0)R to Ty(p)R and Ty(0)L to Ty(p)L output fromthe selection control circuits SR1-R, SR1-L are in a one-to-onecorrespondence with the drive electrodes TL(0) to TL(p). For example,the selection signals Ty(0)R, Ty(0)L correspond to the drive electrodeTL(0), the selection signals Ty(n)R, TY(n)L correspond to the driveelectrode TL(n), and the selection signals Ty(p)R, Ty(p)L correspond tothe drive electrode TL(p). An area where a strong magnetic field is tobe generated (corresponding to a drive electrode) is assigned by theselection signals Ty(0)R to Ty(p)R and Ty(0)L to Ty(p)L from theselection control circuits SR1-R, SR1-L. That is, the switching circuitDSC1 and the selection drive circuit SDC1 are controlled so that astrong magnetic field is generated in an area corresponding to driveelectrodes corresponding to the selection signals set to the high level.For example, if the selection signal Ty(n) is at the high level, theswitching circuit DSC1 and the selection drive circuit SDC1 arecontrolled so that a strong magnetic field is generated in an areacorresponding to the drive electrode TL(n) corresponding to theselection signal Ty(n).

In the second embodiment, the selection signals Ty(0)R to Ty(p)R andTy(0)L to Ty(p)L output from the selection control circuits R1-R, SR1-Lchange to the high level in this order although not specificallylimited. That is, in touch detection, the selection signals Ty(0)R,Ty(0)L change from the low level to the high level, and then, theselection signals Ty(0)R, Ty(0)L change from the high level to the lowlevel, and the selection signals Ty(1)R, Ty(1)L change from the lowlevel to the high level.

In this manner, the high level successively moves from the selectionsignals Ty(0)R, Ty(0)L to the selection signals Ty(p)R, Ty(p)L.Accordingly, in touch detection, a magnetic field is successivelygenerated from the side 2-U toward the side 2-D of the display panel 2(pixel array LCD). That is, in touch detection, a strong magnetic fieldis generated in an area corresponding to the drive electrode TL(0), andnext, a strong magnetic field is generated in an area corresponding tothe close drive electrode TL(1). Hereinafter, a strong magnetic field issuccessively generated in an area corresponding to one drive electrode.Accordingly, the touch on the display panel 2 can be scanned.

<The Switching Circuit DSC1>

The switching circuit DSC1 includes signal wires LL4, LL5, LL6, sixthswitches f00 to f05, and seventh switches g00 to g0 p. Here, the signalwires LL4, LL5 are signal wires that connect drive electrodes in themagnetic field generation period TGT. In the magnetic field generationperiod TGT in the second embodiment, the three signal wires aresubstantially simultaneously formed, and thus, the three signal wiresLL4 to LL6 are provided as signal wires that connect drive electrodes.

The sixth switch f00 is connected between the drive electrode formagnetic field TL(du1) and the signal wire LL4, the sixth switch f01 isconnected between the drive electrode for magnetic field TL(du2) and thesignal wire LL5, and the sixth switch f02 is connected between the driveelectrode for magnetic field TL(du3) and the signal wire LL6. Here, thesixth switches f00 to f02 are switch-controlled by the selection signalsTy(0)R to Ty(2)R from the selection control circuit SR1-R.

Also, the sixth switch f03 is connected between the drive electrode formagnetic field TL(dd1) and the signal wire LL4, the sixth switch f04 isconnected between the drive electrode for magnetic field TL(dd2) and thesignal wire LL5, and the sixth switch f05 is connected between the driveelectrode for magnetic field TL(dd3) and the signal wire LL6. Here, thesixth switches f03 to f05 are switch-controlled by the selection signalsTy(p−2)R to Ty(p)R from the selection control circuit SR1-R.

As different from the sixth switches f00 to f05, each of the seventhswitches g00 to g0 p includes the common terminal c, the first terminalp1, the second terminal p2, and the third terminal. To the seventhswitches g00 to g0 p, the selection signals Ty(0)R to Ty(p)R aresupplied from the selection control circuit SR1-R. Each of the seventhswitches g00 to g0 p connects the common terminal c to the firstterminal p1, the second terminal p2, or the third terminal in accordancewith the supplied selection signal. The third terminal of each of theseventh switches g00 to g0 p is connected to no signal wire and is in afloating state. Thus, as similar to the first switches a00 to a09 inFIG. 11, the third terminal is omitted in FIGS. 23 and 24.

The common terminals c of the seventh switches g00 to g0 p are connectedto ends of the drive electrodes TL(0) to TL(p), respectively. Forexample, the seventh switch g00 corresponds to the drive electrodeTL(0), and the common terminal c of the seventh switch g00 is connectedto an end of the drive electrode TL(0). The seventh switch g04corresponds to the drive electrode TL(n), and the common terminal c ofthe seventh switch g04 is connected to an end of the drive electrodeTL(n). In this manner, the common terminals of the seventh switches areconnected to ends of the corresponding drive electrode, respectively.

The first terminal p1 of each of the seventh switches g01, g02, g05,g08, g0 m, g0 o is connected to the signal wire LL4, the first terminalp1 of each of the seventh switches g03, g06, g09, g0 n, g0 p isconnected to the signal wire LL5, and the first terminal p1 of each ofthe seventh switches g00, g04, g07 is connected to the signal wire LL6.

Also, the second terminal p2 of each of the seventh switches g00, g04,g07 is connected to the signal wire LL4, the second terminal p2 of eachof the seventh switches g01, g02, g05, g08, g0 m, g0 o is connected tothe signal wire LL5, and the second terminal p2 of each of the seventhswitches g03, g06, g09, g0 n, g0 p is connected to the signal wire LL6.

In the magnetic field generation period TGT, the sixth switches f00 tof05 and the seventh switches g00 to g0 p are controlled as follows bythe selection signals Ty(0)R to Ty(p)R output from the selection controlcircuit SR1-R. That is, when a selection signal changes to the highlevel, the common terminal c in three seventh switches connected tothree respective drive electrodes arranged closer to the side 2-U sidethan the drive electrode corresponding to the selection signal at thehigh level is connected to the second terminal p2. At this time, thecommon terminal c in three seventh switches connected to threerespective drive electrodes arranged closer to the side 2-D side thanthe drive electrode corresponding to the selection signal at the highlevel is connected to the first terminal p1. At this time, the commonterminal c in the seventh switches except for these six seventh switchesis connected to the third terminal. In addition, the sixth switches f00to f05 are turned off.

The following is the explanation while exemplifying a case when theselection signal Ty(n+1)R output from the selection control circuitSR1-R is at the high level. Because the selection signal Ty(n+1) ischanged to the high level, the common terminal c in the seventh switchesg04, g03, g02 connected to the drive electrodes TL(n), TL(n−1), TL(n−2)arranged closer to the side 2-U side than the drive electrode TL(n+1)corresponding to the selection signal Ty(n+1) is connected to the secondterminal p2. Also, the common terminal c in the seventh switches g06,g07, g08 connected to the respective drive electrodes TL(n+2), TL(n+3),TL(n+4) arranged closer to the side 2-D side than the drive electrodeTL(n+1) is connected to the first terminal p1. At this time, the commonterminal c in the seventh switches (g05 and g09 to g0 p in FIGS. 23 and24) except for the seventh switches g02 to g04 and g06 to g08 isconnected to the third terminal. At this time, the seventh switches f00to f05 are turned off.

Accordingly, an end of the drive electrode TL(n−2) is connected to thesignal wire LL5 via the seventh switch g02, an end of the driveelectrode TL(n−1) is connected to the signal wire LL6 via the seventhswitch g03, and an end of the drive electrode TL(n) is connected to thesignal wire LL4 via the seventh switch g04. Also, an end of the driveelectrode TL(n+2) arranged on the opposite side of the drive electrodesTL(n) to TL(n−2) across the drive electrode TL(n+1) is connected to thesignal wire LL5 via the seventh switch g06, an end of the driveelectrode TL(n+3) is connected to the signal wire LL6 via the seventhswitch g07, and an end of the drive electrode TL(n+4) is connected tothe signal wire LL4 via the seventh switch g08.

As a result, the drive electrode TL(n−2) and the drive electrode TL(n+2)are connected in series via the signal wire LL5, the drive electrodeTL(n−1) and the drive electrode TL(n+3) are connected in series via thesignal wire LL6, and the drive electrode TL(n) and the drive electrodeTL(n+4) are connected in series via the signal wire LL4. Accordingly,three coils each of which is a single-winding wire are formed of driveelectrodes as winding wires. In this case, an area where the three coilsoverlap with one another is an area corresponding to the drive electrodeTL(n+1) corresponding to the selection signal Ty(n+1) at the high level.

The sixth switches and the seventh switches are controlled as describedabove when any of the selection switches Ty(3)R to Ty(p−3)R is set tothe high level by the selection control circuit SR1-R, so that threecoils overlapping with one another are formed in an area correspondingto the drive electrode corresponding to the high-level selection signal.

Among the selection signals Ty(0) to Ty(p) output from the selectioncontrol circuit SR1-R, if a selection signal corresponding to a driveelectrode close to the side 2-U or the side 2-D of the display panel 2changes to the high level, a drive electrode that forms a coil does notexist in the active area of the display panel 2. For example, when theselection signal Ty(0)R changes to the high level, the drive electrodecorresponding to the selection signal Ty(0)R is the drive electrodeTL(0). For the drive electrode TL(0), while the drive electrodes TL(1)to TL(3) exist on the side 2-D side, no drive electrode exists on theside 2-U side. That is, it is difficult to form a coil having an areacorresponding to the drive electrode TL(0) inside. Therefore, in themagnetic field generation period TGT, it is difficult to generate astrong magnetic field in an area corresponding to the drive electrodeTL(0).

If the selection signal Ty(1)R or the selection signal Ty(2)R changes tothe high level, the number of coils overlapping with each other in anarea corresponding to the drive electrode TL(1) or TL(2) decreases.Thus, the magnetic field generated in the magnetic field generationperiod TGT weakens.

On the other hand, in the second embodiment, a strong magnetic field canbe generated also in an area close to the side 2-U or the side 2-D ofthe display panel 2 by providing a drive electrode for magnetic fieldoutside the active area of the display panel 2.

That is, the sixth switch f00 is controlled so as to be turned on whenthe selection signal Ty(0)R changes to the high level, and the sixthswitch f01 is controlled so as to be turned on when the selection signalTy(0)R or Ty(1)R changes to the high level. Further, the sixth switchf02 is controlled so as to be turned on when any one of the selectionsignals Ty(0)R to Ty(2)R changes to the high level. As similar to theselection signal Ty(n−1)R described above, the common terminal c in thedrive electrodes TL(1) to TL(3) is controlled to be connected to thefirst terminal p1 when any one of the selection signals Ty(0)R to Ty(2)Rchanges to the high level.

Accordingly, when the selection signal Ty(0) is at the high level in themagnetic field generation period TGT, the drive electrode for magneticfield TL(du1) is connected to the signal wire LL4 via the sixth switchf00, the drive electrode for magnetic field TL(du2) is connected to thesignal wire LL5 via the sixth switch f01, and the drive electrode formagnetic field TL(du3) is connected to the signal wire LL6 via the sixthswitch f02. At this time, an end of the drive electrode TL(1) isconnected to the signal wire LL4 via the seventh switch g01. Althoughnot shown in FIG. 23, the drive electrode TL(2) is connected to thesignal wire LL5 via a seventh switch, and the drive electrode TL(3) isconnected to the signal wire LL6 via a seventh switch. That is, threecoils are formed by combining drive electrodes and drive electrodes formagnetic field. Accordingly, three coils whose areas overlap with oneanother can be formed in an area corresponding to the drive electrodeTL(0) in the magnetic field generation period TGT, so that a strongmagnetic field can be generated in the area corresponding to the driveelectrode TL(0).

When the selection signal Ty(1)R is at the high level, one coil isformed of the drive electrode TL(2) not shown and the drive electrodefor magnetic field TL(du2), one coil is formed of the drive electrodeTL(3) not shown and the drive electrode for magnetic field TL(du3), andone coil is formed of the drive electrode TL(0) and the drive electrodeTL(4) not shown. Further, when the selection signal Ty(2)R is at thehigh level, one coil is formed of the drive electrode TL(3) not shownand the drive electrode for magnetic field TL(du3), one coil is formedof the drive electrode TL(4) not shown and the drive electrode TL(0),and one coil is formed of the drive electrode TL(1) and the driveelectrode TL(5) not shown.

Accordingly, the touch detection can be performed even if an area closeto the side 2-U of the display panel 2 is assigned as an area of thetouch detection.

While widths of the drive electrodes for magnetic fields TL(du1) toTL(du3) are different from one another in the second embodiment, theymay be the same as one another. Alternatively, the drive electrodes formagnetic fields TL(du1) to TL(du3) may be made narrower in width in thisorder. The drive electrodes for magnetic field do not affect thedisplay. Therefore, in order to suppress the widening of the perimeter(frame) of the display panel 2, the widths of the drive electrodes formagnetic fields TL(du1) to TL(du3) are desirably narrower than the widthd4 of the drive electrode TL.

As shown in FIG. 24, the drive electrodes for magnetic fields TL(dd1) toTL(dd3) are arranged outside the active area of the display panel 2along the side 2-D of the display panel 2. The drive electrodes formagnetic fields TL(dd1) to TL(dd3) and the sixth switches f03 to f05operate as similar to the drive electrodes for magnetic fields TL(du1)to TL(du3) and the sixth switches f00 to f02.

Thus, although a detailed description is omitted, when the selectionsignal Ty(p)R changes to the high level, a coil is formed of the driveelectrode for magnetic field TL(dd1) and the drive electrode TL(p−1), acoil is formed of the drive electrode for magnetic field TL(dd2) and thedrive electrode TL(p−2) not shown, and a coil is formed of the driveelectrode for magnetic field TL(dd3) and the drive electrode TL(p−3) notshown. Also, when the selection signal Ty(p−1)R changes to the highlevel, a coil is formed of the drive electrode for magnetic fieldTL(dd2) and the drive electrode TL(p−2) not shown, a coil is formed ofthe drive electrode for magnetic field TL(dd3) and the drive electrodeTL(p−3) not shown, and a coil is formed of the drive electrode TL(p) andthe drive electrode TL(p−4) not shown. Further, when the selectionsignal Ty(p−2)R changes to the high level, a coil is formed of the driveelectrode for magnetic field TL(dd3) and the drive electrode TL(p−3), acoil is formed of the drive electrode TL(p) and the drive electrodeTL(p−4) not shown, and a coil is formed of the drive electrode TL(p−1)and the drive electrode TL(p−5).

Accordingly, the touch detection can be performed even if an area closeto the side 2-D of the display panel 2 is assigned as an area of thetouch detection.

<The Selection Drive Circuit SDC1>

The selection drive circuit SDC1 includes the voltage wire VL1, thevoltage wire VL2, the signal wire LL3, eighth switches h00 to h05, andninth switches i00 to i0 p. As similar to the first embodiment, thedisplay drive signal VCOMDC is supplied to the voltage wire VL1 indisplay, and, for example, the ground voltage Vss is supplied to thevoltage wire VL2 in the magnetic field generation period TGT. Also, thecoil clock signal CCLK is supplied to the signal wire LL3 in themagnetic field generation period TGT.

The eighth switch h00 is connected between the signal wire LL3 and anend of the drive electrode for magnetic field TL(du1), the eighth switchh01 is connected between the signal wire LL3 and an end of the driveelectrode for magnetic field TL(du2), and the eighth switch h02 isconnected between the signal wire LL3 and an end of the drive electrodefor magnetic field TL(du3). Also, the eighth switch h03 is connectedbetween the voltage wire VL2 and an end of the drive electrode formagnetic field TL(dd1), the eighth switch h04 is connected between thevoltage wire VL2 and an end of the drive electrode for magnetic fieldTL(dd2), and the eighth switch h05 is connected between the voltage wireVL2 and an end of the drive electrode for magnetic field TL(dd3).

Each of these eighth switches h00 to h05 is controlled by the selectionsignals Ty(0)L to Ty(2)L and Ty(p−2)L to Ty(p)L from the selectioncontrol circuit SR1-L. That is, the eighth switches h00 to h05 areturned on or turned off by the selection signals Ty(0)L to Ty(2)L andTy(p−2)L to Ty(p)L.

Each of the ninth switches i00 to i0 p includes the common terminal cconnected to an end of the corresponding drive electrode, the firstterminal p1 connected to the voltage wire VL1, the second terminal p2connected to the signal wire LL3, the third terminal p3 connected to thevoltage wire VL2, and the fourth terminal. The fourth terminal of eachof the ninth switches i00 to i0 p is connected to no signal wire and isin a floating state. Thus, as similar to the second switches b00 to b09shown in FIG. 11, the fourth terminal is omitted in FIGS. 23 and 24.

These ninth switches i00 to i0 p are also controlled by the selectionsignals Ty(0)L to Ty(p)L from the selection control circuit SR1-L.However, as different from the eighth switches h00 to h05, the commonterminal c is connected to any one of the first terminal p1, the secondterminal p2, the third terminal p3, and the fourth terminal inaccordance with the supplied selection signal.

As similar to each of the selection signals Ty(0)R to Ty(p)R output fromthe selection circuit SR1-R, each of the selection signals Ty(0)L toTy(p)L output from the selection control circuit SR1-L is in aone-to-one correspondence with the drive electrodes TL(0) to TL(p). Whena selection signal output from the selection control circuit SR1-L is atthe high level, the ninth switches i00 to i0 p are controlled so that amagnetic-field drive signal and the ground voltage Vss are supplied tothree coils overlapping with one another in an area corresponding to thedrive electrode corresponding to the high-level selection signal.

That is, when a selection signal changes to the high level, in threeninth switches connected to three respective drive electrodes arrangedcloser to the side 2-U side than the drive electrode corresponding tothe selection signal, the common terminal c is controlled to beconnected to the second terminal p2. At this time, in three ninthswitches connected to three respective drive electrodes arranged closerto the side 2-D side than the drive electrode corresponding to theselection signal, the common terminal c is controlled to be connected tothe third terminal p3. Also at this time, in the ninth switches exceptfor these six ninth switches, the common terminal c is connected to thefourth terminal. Also, the eighth switches h00 to h05 are turned off.

As similar to the selection control circuit SR1-R, the following is theexplanation while exemplifying a case when the selection signal Ty(n+1)Loutput from the selection control circuit SR1-L is at the high level.When the selection signal Ty(n+1)L is changed to the high level, in theninth switches i04, i03, i02 connected to the respective driveelectrodes TL(n), TL(n−1), TL(n−2) arranged closer to the side 2-U sidethan the drive electrode TL(n+1) corresponding to the selection signalTy(n+1)L, the common terminal c is connected to the second terminal p2.Also, in the ninth switches i06, i07, i08 connected to the respectivedrive electrodes TL(n+2), TL(n+3), TL(n+4) arranged closer to the side2-D side than the drive electrode TL(n+1), the common terminal c isconnected to the third terminal p3. At this time, in the ninth switches(i05 and i09 to i0 p in FIGS. 23 and 24) except for the ninth switchesi02 to i04 and i06 to i08, the common terminal c is connected to thefourth terminal. At this time, the eighth switches h00 to h05 are turnedoff.

Accordingly, an end of the drive electrode TL(n−2) is connected to thesignal wire LL3 via the ninth switch i02, an end of the drive electrodeTL(n−1) is connected to the signal wire LL3 via the ninth switch i03,and an end of the drive electrode TL(n) is connected to the signal wireLL3 via the ninth switch i04. Also, an end of the drive electrodeTL(n+2) arranged on the opposite side of the drive electrodes TL(n) toTL(n−2) across the drive electrode TL(n+1) is connected to the voltagewire VL2 via the ninth switch i06, an end of the drive electrode TL(n+3)is connected to the voltage wire VL2 via the ninth switch i07, and anend of the drive electrode TL(n+4) is connected to the voltage wire VL2via the ninth switch i08.

At this time, as described above, by the switching circuit DSC1, thedrive electrode TL(n−2) and the drive electrode TL(n+2) are connected inseries via the signal wire LL5, the drive electrode TL(n−1) and thedrive electrode TL(n+3) are connected in series via the signal wire LL6,and the drive electrode TL(n) and the drive electrode TL(n+4) areconnected in series via the signal wire LL4. That is, three coils eachof which is a single-winding wire are formed of drive electrodes aswinding wires.

The ground voltage Vss of the voltage wire VL2 is supplied to an end ofeach of the drive electrodes TL(n+2), TL(n+3), TL(n+4) via the ninthswitches i06 to i08. Also, the coil clock signal CCLK of the signal wireLL3 is supplied to an end of each of the drive electrodes TL(n−2),TL(n−1), TL(n) via the ninth switches i02 to i04 in parallel in terms oftime.

As a result, a magnetic-field drive signal is supplied to the threecoils whose areas overlap with one another in an area corresponding tothe drive electrode TL(n+1) substantially at the same time, so that astrong magnetic field is generated in the area corresponding to thedrive electrode TL(n+1).

The eighth switch h00 is controlled to be turned on when the selectionsignal Ty(0)L changes to the high level, and the eighth switch h01 iscontrolled to be turned on when either one of the selection signalsTy(0)L and Ty(1)L changes to the high level. Further, the eighth switchh02 is controlled to be turned on when any one of the selection signalsTy(0)L to Ty(2)L changes to the high level. On the other hand, in eachof the ninth switches i01 to i03, the common terminal c is controlled tobe connected to the third terminal p3 when the selection signals Ty(0)Lto Ty(2)L are set to the high level as similar to the selection signalTy(n+1)L described above.

Accordingly, when the selection signal Ty(0)L is at the high level, thedrive electrode for magnetic field TL(du1) is connected to the signalwire LL3 via the eighth switch h00, the drive electrode for magneticfield TL(du2) is connected to the signal wire LL3 via the eighth switchh01, and the drive electrode for magnetic field TL(du3) is connected tothe signal wire LL3 via the eighth switch h02. At this time, an end ofthe drive electrode TL(1) is connected to the voltage wire VL2 via theninth switch i01. Although not shown in FIG. 23, the drive electrodeTL(2) is connected to the voltage wire VL2 via the ninth switch i02 andthe drive electrode TL(3) is connected to the voltage wire VL2 via theninth switch i03. Accordingly, the magnetic-field drive signal and theground voltage Vss are supplied to each of three coils formed bycombining the drive electrodes TL(1) to TL(3) and the drive electrodesfor magnetic field TL(du1) to TL(du3) substantially at the same time. Asa result, in the magnetic field generation period TGT, three coils whoseareas overlap with one another can be formed in an area corresponding tothe drive electrode TL(0), so that a strong magnetic field can begenerated in the area corresponding to the drive electrode TL(0).

Similarly, when the selection signal Ty(1)L corresponding to the driveelectrode TL(1) changes to the high level, a magnetic-field drive signaland the ground voltage Vss are supplied to three coils formed bycombining the drive electrodes for magnetic field TL(du2), TL(du3), thedrive electrode TL(0), and the drive electrodes TL(2) to TL(4) notshown. In this case, the eighth switches h01, h02 are turned on, thecommon terminal c of the ninth switch i00 is connected to the secondterminal p2, and the common terminal c of the ninth switches i01, i02,i03 is connected to the third terminal p3. Also, when the selectionsignal Ty(2)L corresponding to the drive electrode TL(2) changes to thehigh level, a magnetic-field drive signal and the ground voltage Vss aresupplied to three coils formed by combining the drive electrode formagnetic field TL(du3), the drive electrode TL(0), TL(1), and a driveelectrode not shown.

A case when the drive electrodes TL(p), TL(p−1), TL(p−2) arranged on theside 2-D side of the display panel 2 are assigned as an area of thetouch detection is similar. That is, when the selection signal Ty(p)Lcorresponding to the drive electrode TL(p) changes to the high level, amagnetic-field drive signal and the ground voltage Vss are supplied tothree coils formed by combining the drive electrodes for magnetic fieldTL(dd1) to TL(dd3), the drive electrode TL(p−1), and the driveelectrodes TL(p−2), TL(p−3) not shown. In this case, the eighth switchesh03 to h05 are turned on, and the common terminal c in a ninth switche(a reference character i0 o is exemplified in FIG. 24) connected to eachof the drive electrodes TL(p−1) to TL(p−3) is connected to the secondterminal p2.

Also, when the selection signal Ty(p−1)L corresponding to the driveelectrode TL(p−1) changes to the high level, a magnetic-field drivesignal and the ground voltage Vss are supplied to three coils formed bycombining the drive electrodes for magnetic field TL(dd2), TL(dd3), thedrive electrode TL(p), and the drive electrodes TL(p−2) to TL(p−4) notshown. In this case, the eighth switches h04, h05 are turned on, and thecommon terminal c in the ninth switch i0 p and ninth switches connectedto the drive electrodes TL(p−2), TL(p−3) is connected to the secondterminal p2. Further, when the selection signal Ty(p−2)L correspondingto the drive electrode TL(p−2) changes to the high level, amagnetic-field drive signal and the ground voltage Vss are supplied tothree coils formed by combining the drive electrode for magnetic fieldTL(dd3), the drive electrodes TL(p), TL(p−1), and the drive electrodesTL(p−3) to TL(p−5) not shown.

Thus, the eighth switches h00 to h05 and the ninth switches i00 to i0 pare controlled as described above by the state in which thecorresponding selection signals Ty(0)L to Ty(p)L are changed to the highlevel by the selection control circuit SR1-L, and a magnetic-field drivesignal and the ground voltage Vss are supplied substantially at the sametime to three coils overlapping with one another in an areacorresponding to the drive electrode corresponding to the high-levelselection signal.

When, for example, the magnetic-field enable signal SC_EN is at the lowlevel, the selection control circuit SR1-L performs such control thatthe common terminals c of each of the ninth switches i00 to i0 p isconnected to the first terminal p1. In the display period, themagnetic-field enable signal SC_EN is set to the low level. Thus, in thedisplay period, the ninth switches i00 to i0 p connect the respectivedrive electrodes TL(0) to TL(p) to the voltage wire VL1. In the displayperiod, the display drive signal VCOMDC is supplied to the voltage wireVL1, and thus, a display drive signal is supplied from the selectiondrive circuit SDC1 to the respective drive electrodes TL(0) to TL(p) inthe display period.

The common terminal c of each of the seventh switches g00 to g0 p may beconnected to a fourth terminal when the voltage wire VL1 is alsoprovided to the switching circuit DSC1, when the fourth terminalconnected to the voltage wire VL1 is provided to each of the seventhswitches g00 to g0 p, and when the magnetic-field enable signal SC_EN isat the low level. In this manner, a display drive signal can also besupplied from the switching circuit DSC1 to the drive electrodes TL(0)to TL(P) in the display period. That is, in the display period, adisplay drive signal can be supplied from both ends of the driveelectrodes TL(0) to TL(p).

<Operation of Touch Detection>

Next, the operation of touch detection in the liquid crystal displayapparatus 1 according to the second embodiment will be described withreference to FIGS. 25 to 28. Each of FIGS. 25 to 28 shows a state inwhich the sixth switches f00 to f05, the seventh switches g00 to g0 p,the eighth switches h00 to h05, and the ninth switches i00 to i0 p arecontrolled by the selection control circuits SR1-R, SR1-L shown in FIGS.23 and 24 in the magnetic field generation period TGT. In FIGS. 25 to28, the eighth switches h00 to h05 and the ninth switches i00 to i0 pare omitted in order to avoid the complexity of the drawings, and drivecurrents supplied by connecting the common terminal c in the ninthswitch to the second terminal p2 or the third terminal p3 are shown asreference characters I1 to I4. In the magnetic field generation periodTGT, the drive current flows by the supply of the magnetic-field drivesignal to the coil, and thus, the reference characters I1 to I4 can alsobe considered to show magnetic-field drive signals.

Drive electrodes except for drive electrodes to which the drive currents(magnetic-field drive signals) I1 to I4 are supplied are in a floatingstate. That is, the sixth switches and the eighth switches connected todrive electrodes to which the magnetic-field drive signals I1 to I4 arenot supplied are turned off. The common terminal c in the seventhswitches connected to drive electrodes to which the magnetic-field drivesignals I1 to I4 are not supplied is connected to the third terminal p3,and the common terminal c in the ninth switch is connected to the fourthterminal.

Here is the explanation as an example for a case when a strong magneticfield is successively generated from an area corresponding to the driveelectrode TL(n+1) to an area corresponding to the drive electrodeTL(n+4) by a scan operation. A case when a strong magnetic field isgenerated in other areas is also similar. The operation to generate astrong magnetic field by combining the drive electrodes for magneticfield TL(du1) to TL(du3) and TL(dd1) to TL(dd3) and drive electrodes hasbeen described above, and thus, the description thereof is omitted here.

The selection control circuits SR1-R, SR1-L successively set selectionsignals to the high level in the order of the selection signals Ty(0)R,Ty(0)L to the selection signals Ty(p)R, Ty(p)L from the side 2-U towardthe side 2-D of the display panel 2. In exemplifying the FIGS. 25 to 28,the selection control circuits SR1-R, SR1-L set the selection signalsTy(n+1)R, Ty(n+1)L to the high level in touch detection in the magneticfield generation period TGT, and set the selection signals Ty(n+2)R,Ty(n+2)L to the high level in the next magnetic field generation periodTGT. In the subsequent magnetic field generation period TGT, theselection control circuits SR1-R, SR1-L set the selection signalsTy(n+3)R, Ty(n+3)L to the high level. In the still subsequent magneticfield generation period TGT, they set the selection signals Ty(n+4)R,Ty(n+4)L to the high level. In any of the magnetic field generationperiods TGT, selection signals except for the selection signals set tothe high level are set to the low level.

FIG. 25 shows a state in which the selection signals Ty(n+1)R, Ty(n+1)Lare at the high level, and FIG. 26 shows a state in which the selectionsignals Ty(n+2)R, Ty(n+2)L are at the high level. Similarly, FIG. 27shows a state in which the selection signals Ty(n+3)R, Ty(n+3)L are atthe high level, and FIG. 28 shows a state in which the selection signalsTy(n+4)R, Ty(n+4)L are at the high level.

As described with reference to FIGS. 23 and 24, by the state in whichthe selection signal Ty(n+1)R is at the high level, the common terminalc in each of the seventh switches g02 to g04 is connected to the secondterminal p2, and the common terminal c in each of the seventh switchesg06 to g08 is connected to the first terminal p1. Accordingly, the driveelectrodes TL(n−2), TL(n+2) are connected to the signal wire LL5 via theseventh switches g02, g06, the drive electrodes TL(n−1), TL(n+3) areconnected to the signal wire LL6 via the seventh switches g03, g07, andthe drive electrodes TL(n), TL(n+4) are connected to the signal wire LL4via the seventh switches g03, g07. As a result, the coil CY(n) havingthe drive electrodes TL(n−2), TL(n+2) as winding wires is formed, thecoil CY(n+1) having the drive electrodes TL(n−1), TL(n+3) as windingwires is formed, and the coil CY(n+2) having the drive electrodes TL(n),TL(n+4) as winding wires is formed (see FIG. 15).

In this case, the coil CY(n) becomes a coil having an area correspondingto the drive electrodes TL(n−1) to TL(n+1) inside, the coil CY(n+1)becomes a coil having an area corresponding to the drive electrodesTL(n) to TL(n+2) inside, and the coil CY(n+2) becomes a coil having anarea corresponding to the drive electrodes TL(n+1) to TL(n+3) inside.Thus, the coil CY(n) and the coil CY(n+1) overlap in an areacorresponding to the drive electrodes TL(n), TL(n+1), the coil CY(n) andthe coil CY(n+2) overlap in an area corresponding to the drive electrodeTL(n+1), and the coil CY(n+1) and the coil CY(n+2) overlap in an areacorresponding to the drive electrodes TL(n), TL(n+1). The area where thethree coils CY(n) to CY(n+2) overlap is an area corresponding to thedrive electrode TL(n+1).

When each of the coils CY(n) to CY(n+2) is formed, that is, when theperiod is the magnetic field generation period TGT, the selection signalTy(n+1)L also changes to the high level, and thus, the common terminal cin each of the ninth switches i02 to i04 is connected to the secondterminal p2, and the common terminal c in each of the ninth switches i06to i08 is connected to the third terminal p3. As a result, to therespective terminals PTL(n−2) to PTL(n) of the coils CY(n) to CY(n+2),the coil clock signal CCLK is supplied from the signal wire LL3 as themagnetic-field drive signal. The magnetic-field drive signal istransferred in drive electrodes forming the coils CY(n) to CY(n+2) andin signal wires, and is transferred from the respective terminalsPTL(n+2) to PTL(n+4) to the voltage wire VL2.

The coil clock signal CCLK is a periodically-changing signal, and thus,each of the coils CY(n) to CY(n+2) generates a magnetic field changingin accordance with changes of the magnetic-field drive signal. Themagnetic-field drive signal is supplied to the coils CY(n) to CY(n+2)substantially at the same time. Thus, magnetic fields are superimposedin an area where the inner sides of the coils CY(n) to CY(n+2) overlap.In such a case, magnetic fields generated by two coils are superimposedin an area where the two coils overlap. Particularly, the areacorresponding to the drive electrode TL(n) is an area where the threecoils CY(n) to CY(n+2) overlap, and thus, magnetic fields generated bythe three coils are superimposed in the area corresponding to the driveelectrode TL(n), so that the strongest magnetic field is generatedtherein.

In the touch detection, signal are changed in the coils CX(0) to CX(p)formed by using signal lines depending on whether an area correspondingto the drive electrode TL(n+1) is touched by a pen or not in themagnetic field detection period TDT as described with reference to FIGS.16 to 18, and the signals are output as sense signals.

Subsequent to the selection signals Ty(n+1)R, Ty(n+1)L, the selectioncontrol circuits SR1-R, SR1-L set the selection signals Ty(n+2)R,Ty(n+2)L to the high level. At this time, the selection signalsTy(n+1)R, Ty(n+1)L change to the low level. As shown in FIG. 26, by thestate in which the selection signals Ty(n+2)R, Ty(n+2)L are changed tothe high level, the common terminal c in each of the seventh switchesg03 to g05 is connected to the second terminal p2, and the commonterminal c in each of the seventh switches g07 to g09 is connected tothe first terminal p1. As a result, the drive electrodes TL(n−1),TL(n+3) are connected to the signal wire LL6, the drive electrodesTL(n), TL(n+4) are connected to the signal wire LL4, and the driveelectrodes TL(n+1), TL(n+5) are connected to the signal wire LL5.Accordingly, the coils CY(n+1) to CY(n+3) having these drive electrodesas winding wires are formed substantially at the same time. In thiscase, the area where the three coils CY(n+1) to CY(n+3) overlap with oneanother is an area corresponding to the drive electrode TL(n+2).

On the other hand, by the state in which the selection control signalTy(n+2)L is changed to the high level, the common terminal c in each ofthe ninth switches i03 to i05 is connected to the second terminal p2,and the common terminal c in each of the ninth switches i07 to i09 isconnected to the third terminal p3. As a result, the terminals PTL(n−1)to PTL(n+1) of the coils CY(n+1) to CY(n+3) are connected to the signalwire LL3, and the terminals PTL(n+3) to PTL(n+5) of the coils CY(n+1) toCY(n+3) are connected to the voltage wire VL2. Accordingly, in themagnetic field generation period TGT, the coil clock signal CCLK issupplied to the terminals PTL(n−1) to PTL(n+1) of the coils CY(n+1) toCY(n+3) as the magnetic-field drive signal, and the magnetic-field drivesignal is transferred to the voltage wire VL2 via these coils.

Accordingly, as similar to the case of FIG. 25, a magnetic field isgenerated by each of the coils CY(n+1) to CY(n+3). In the case of FIG.26, magnetic fields generated by the three coils are superimposed in thearea corresponding to the drive electrode TL(n+2), so that the strongestmagnetic field is generated therein.

In the touch detection, signal are changed in the coils CX(0) to CX(p)formed by using signal lines depending on whether an area correspondingto the drive electrode TL(n+2) is touched by a pen or not in themagnetic field detection period TDT as described with reference to FIGS.16 to 18, and the signals are output as sense signals.

Subsequent to the selection signals Ty(n+2)R, Ty(n+2)L, the selectioncontrol circuits SR1-R, SR1-L set the selection signals Ty(n+3)R,Ty(n+3)L to the high level. At this time, the selection signalsTy(n+2)R, Ty(n+2)L change to the low level. As shown in FIG. 27, by thestate in which the selection signals Ty(n+3)R, Ty(n+3)L are changed tothe high level, the common terminal c in each of the seventh switchesg04 to g06 is connected to the second terminal p2, and the commonterminal c in each of the seventh switches g08 to g10 is connected tothe first terminal p1. As a result, the drive electrodes TL(n), TL(n+4)are connected to the signal wire LL4, the drive electrodes TL(n+1),TL(n+5) are connected to the signal wire LL5, and the drive electrodesTL(n+2), TL(n+6) are connected to the signal wire LL6. Accordingly, thecoils CY(n+2) to CY(n+4) having these drive electrodes as winding wiresare formed substantially at the same time. In this case, the area wherethe three coils CY(n+2) to CY(n+4) overlap with one another is an areacorresponding to the drive electrode TL(n+3).

On the other hand, by the state in which the selection control signalTy(n+3)L is changed to the high level, the common terminal c in each ofthe ninth switches i04 to i06 is connected to the second terminal p2,and the common terminal c in each of the ninth switches i08 to i10 isconnected to the third terminal p3. As a result, the terminals PTL(n) toPTL(n+2) of the coils CY(n+2) to CY(n+4) are connected to the signalwire LL3, and the terminals PTL(n+4) to PTL(n+6) of the coils CY(n+2) toCY(n+4) are connected to the voltage wire VL2. Accordingly, in themagnetic field generation period TGT, the coil clock signal CCLK issupplied to the terminals PTL(n) to PTL(n+2) of the coils CY(n+2) toCY(n+4) as the magnetic-field drive signal, and the magnetic-field drivesignal is transferred to the voltage wire VL2 via these coils.

Accordingly, as similar to the case of FIG. 25, a magnetic field isgenerated by each of the coils CY(n+2) to CY(n+4). In the case of FIG.27, magnetic fields generated by the three coils are superimposed in thearea corresponding to the drive electrode TL(n+3), so that the strongestmagnetic field is generated therein.

Subsequent to the selection signals Ty(n+3)R, Ty(n+3)L, the selectioncontrol circuits SR1-R, SR1-L set the selection signals Ty(n+4)R,Ty(n+4)L to the high level. At this time, the selection signalsTy(n+3)R, Ty(n+3)L change to the low level. As shown in FIG. 28, by thestate in which the selection signals Ty(n+4)R, Ty(n+4)L are changed tothe high level, the common terminal c in each of the seventh switchesg04 to g06 is connected to the second terminal p2, and the commonterminal c in each of the seventh switches g08 to g10 is connected tothe first terminal p1. As a result, the drive electrodes TL(n+1),TL(n+5) are connected to the signal wire LL5, the drive electrodesTL(n+2), TL(n+6) are connected to the signal wire LL6, and the driveelectrodes TL(n+3), TL(n+7) are connected to the signal wire LL4.Accordingly, the coils CY(n+3) to CY(n+5) having these drive electrodesas winding wires are formed substantially at the same time. In thiscase, the area where the three coils CY(n+3) to CY(n+5) overlap with oneanother is an area corresponding to the drive electrode TL(n+4).

On the other hand, by the state in which the selection control signalTy(n+4)L is changed to the high level, the common terminal c in each ofthe ninth switches i05 to i07 is connected to the second terminal p2,and the common terminal c in each of the ninth switches i09 to i11 isconnected to the third terminal p3. As a result, each one terminal ofthe coils CY(n+3) to CY(n+5) is connected to the signal wire LL3, andeach other terminal of the coils CY(n+2) to CY(n+4) is connected to thevoltage wire VL2. Accordingly, in the magnetic field generation periodTGT, the coil clock signal CCLK is supplied to each one terminal of thecoils CY(n+3) to CY(n+5) as the magnetic-field drive signal, and themagnetic-field drive signal is transferred to the voltage wire VL2 viathese coils.

Accordingly, as similar to the case of FIG. 25, a magnetic field isgenerated by each of the coils CY(n+3) to CY(n+5). In the case of FIG.28, magnetic fields generated by the three coils are superimposed in thearea corresponding to the drive electrode TL(n+4), so that the strongestmagnetic field is generated therein.

In the second embodiment, three coils (for example, CY(n+2) to CY(n))are formed by using drive electrodes (for example, TL(n−2) to TL(n) andTL(n+2) to TL(n+4)) arranged close to each other as winding wires in themagnetic field generation period TGT. To the formed three coils, themagnetic-field drive signal is supplied substantially at the same time.An area where the inner sides the three coils overlap with one anotherbecomes an area corresponding to the drive electrode (TL(n+1))sandwiched between drive electrodes to be winding wires of the coils. Inthe area where the coils overlap, magnetic fields generated by each ofthe three coils are superimposed to generate the strongest magneticfield. If a pen approaches an area where coils overlap in touchdetection, the pen internal coil L1 generates an induced voltage by astrong magnetic field, and thus, the amount of charge to be charged inthe capacitative element C in the pen can be increased, so that theaccuracy of detection can be improved. Because each coil is asingle-winding coil, decrease in the drive current flowing through eachcoil can be prevented, so that the weakening of the magnetic fieldgenerated by each coil can be suppressed.

In the second embodiment, three single-winding coils are formed in themagnetic field generation period TGT, and a strong magnetic field isgenerated in an area where the three coils overlap. In a scan operation,three coils are formed while being shifted from the side 2-U side towardthe side 2-D side of the display panel 2. The width of the shifted areacorresponds to the width of one drive electrode corresponding to thearea where the touch should be detected. Therefore, the area where thetouch is detected can be prevented from being discontinuous, so thatoccurrence of an area where the accuracy of detection is degraded can beprevented.

The drive electrodes for magnetic field are provided outside the activearea of the display panel 2 along the side 2-U and the side 2-D of thedisplay panel 2. When an area close to the side 2-U or the side 2-D ofthe display panel 2 is set as an area of touch detection, a strongmagnetic field can be generated also in an area close to the side 2-U orthe side 2-D of the display panel 2 by using a drive electrode formagnetic field as a winding wire for forming a coil. As a result, thedegradation of the accuracy of detection can be prevented in an areaclose to a side of the display panel 2.

An example in which the drive electrodes for magnetic field TL(du1) toTL(du3) and TL(dd1) to TL(dd3) to be winding wires for forming a coilare provided outside the active area of the display panel 2, that is,outside the display area has been described. However, the presentembodiment is not limited to such an example. For example, even insidethe active area of the display panel 2, one or a plurality of driveelectrodes for magnetic field may be provided along the side 2-U or theside 2-D of the display panel 2. In such a case, narrowing of thedisplay area can be reduced by making the width of drive electrodes formagnetic field narrower.

Third Embodiment

FIG. 29 is an explanatory diagram showing the configuration of theliquid crystal display apparatus 1 according to the third embodiment.FIG. 29 shows an operation in touch detection. This drawing shows such aconfiguration as generating a magnetic field by a coil formed of driveelectrodes in the magnetic field generation period TGT and as detectinga magnetic field from a pen PN by a coil formed of signal lines in themagnetic field detection period TDT.

The left side of FIG. 29 shows a state of the magnetic field generationperiod TGT, in which an induced voltage is generated in the coil L1inside the pen PN shown on the upper side of FIG. 29 by a magnetic fieldgenerated in the magnetic field generation period TGT, and in which thecapacitative element C (not shown) inside the pen PN is charged by theinduced voltage generated in the coil L1. In the magnetic fielddetection period TDT, the coil L1 inside the pen PN generates a magneticfield by charges charged in the capacitative element C. The generatedmagnetic field is detected by a coil formed of signal lines shown on theright side of FIG. 29.

First, the state of the magnetic field generation period TGT shown onthe left side of FIG. 29 will be described. The left side of FIG. 29shows the drive electrodes TL(0) to TL(p) arranged in the display panel2, the drive electrodes for magnetic field TL(du1) to TL(du3), TL(dd1)to TL(dd3) arranged outside the active area of the display panel 2, thesixth switches f00 to f05, and the seventh switches g00 to g0 p. Theconfigurations of these drive electrodes, drive electrodes for magneticfield, sixth switches, and seventh switches are the same as those shownin FIGS. 23 to 28. Also, as similar to FIG. 26, the left side of FIG. 29shows a state in which the common terminal c in the seventh switches g02to g04 is connected to the second terminal p2 and the common terminal cin the seventh switches g06 to g08 is connected to the first terminalp1. Accordingly, as described with reference to FIG. 26, the coilsCY(n−1) to CY(n+1) are formed.

In the magnetic field generation period TGT, the coil clock signal CCLKis supplied to each of one ends PTL(n−1) to PTL(n+1) of the formed coilsCY(n−1) to CY(n+1) as a magnetic-field drive signal, and the groundvoltage Vss is supplied to each of the other ends PTL(n+3) to PTL(n+5)of the coils CY(n−1) to CY(n+1). Accordingly, in the magnetic fieldgeneration period TGT, the strongest magnetic field is generated in anarea where these coils overlap with each other, that is, an areacorresponding to the drive electrode TL(n−2).

By the state in which the pen PN exists in vicinity of the driveelectrode TL(n−2), an induced voltage is generated in the coil L1 insidethe pen PN, so that the capacitative element C inside the pen PN ischarged.

Next, the configuration shown on the right side of FIG. 29 will bedescribed. Also in the third embodiment, as similar to the firstembodiment, a plurality of coils are formed of signal lines in themagnetic field detection period TDT. In the third embodiment, each ofcoils formed of signal lines is a single-winding coil as different fromthe first embodiment.

In the third embodiment, although not specifically limited, signal linesfor magnetic field SL(dR), SL(dL) are arranged along the sides 2-R, 2-Lof the display panel 2. That is, the liquid crystal display apparatus 1includes the signal line for magnetic field SL(dR) (second signal line)arranged to be parallel to the signal lines SL(0) to SL(p) (first signallines) along the side 2-R outside the active area of the display panel 2and the signal line for magnetic field SL(dL) (second signal line)arranged to be parallel to the signal lines SL(0) to SL(p) along theside 2-R outside the active area of the display panel 2. The signallines for magnetic field SL(dR), SL(dL) are outside the active area ofthe display panel 2, and thus, do not contribute to the display and areused in the touch detection.

If the display panel 2 is corresponded to the pixel array LCD, note thatthe signal lines for magnetic field SL(dR), SL(dL) are arranged alongsides of the pixel array LCD and parallel to the column of the pixelarray LCD. That is, the signal line for magnetic field SL(dR) isarranged along the side of the pixel array LCD corresponding to the side2-R of the display panel 2, and the signal line for magnetic fieldSL(dL) is arranged along the side of the pixel array LCD correspondingto the side 2-L of the display panel 2.

In the third embodiment, the switching adjustment circuit SCX-U isarranged along the side 2-U side of the display panel 2. In FIG. 29, theupper side shows the side 2-U side of the display panel 2, and the lowerside shows the side 2-D side of the display panel 2. The switchingadjustment circuit SCX-U includes tenth switches j00, j01 and eleventhswitches k00 to kp.

Although not specifically limited, the signal lines SL(0) to SL(p) arearranged in this order from the side 2-L toward the side 2-R of thedisplay panel 2. In the magnetic field detection period TDT in the thirdembodiment, signal lines arranged so as to sandwich two signal linestherebetween are connected by the eleventh switches k00 to kp. In thedescription of FIG. 29 as an example, the eleventh switch k00 isconnected between an end of the signal line SL(1) and an end of thesignal line SL(4), and the eleventh switch k01 is connected between anend of the signal line SL(3) and an end of the signal line SL(6). Also,the eleventh switch kn−1 is connected between an end of the signal lineSL(n−2) and an end of the signal line SL(n+1), the eleventh switch kn isconnected between an end of the signal line SL(n) and an end of thesignal line SL(n+3), and the eleventh switch kn+1 is connected betweenan end of the signal line SL(n+2) and an end of the signal line SL(n+5).

Further, the eleventh switch kp−1 is connected between an end of thesignal line SL(p−6) and an end of the signal line SL(p−3), and theeleventh switch kp is connected between an end of the signal lineSL(p−4) and an end of the signal line SL(p−1).

The tenth switch j00 is connected between an end of the signal line formagnetic field SL(dL) and an end of the signal line SL(2), and the tenthswitch j01 is connected between an end of the signal line for magneticfield SL(dR) and an end of the signal line SL(p−2).

Each of the tenth switches j00, j01 and the eleventh switches k00 to kpis switch-controlled by the magnetic-field enable signal SC_EN. In thethird embodiment, the tenth switches j00, j01 and the eleventh switchesk00 to kp are turned on when the magnetic-field enable signal SC_EN isat the high level, and are turned off when the magnetic-field enablesignal SC_EN is at the low level.

The magnetic-field enable signal SC_EN is set to the high level in thetouch detection, and thus, the tenth switches and the eleventh switchesare turned on. As a result, in the touch detection, signal linessandwiching two signal lines therebetween are electrically connected toeach other. In the description of FIG. 29 as an example, the signallines SL(1), SL(4) arranged so as to sandwich the signal lines SL(2),SL(3) therebetween are electrically connected to each other by theeleventh switch k00. Similarly, the signal lines SL(3), SL(6) arrangedso as to sandwich the signal lines SL(4), SL(5) therebetween areconnected to each other by the eleventh switch k01, the signal linesSL(n−2), SL(n+1) arranged so as to sandwich the signal lines SL(n−1),SL(n) therebetween are connected to each other by the eleventh switchkn−1, the signal lines SL(n), SL(n+3) arranged so as to sandwich thesignal lines SL(n+1), SL(n+2) therebetween are connected to each otherby the eleventh switch kn, and the signal lines SL(n+2), SL(n+5)arranged so as to sandwich the signal lines SL(n+3), SL(n+4)therebetween are connected to each other by the eleventh switch kn+1.

Further, the signal lines SL(p−6), SL(p−3) arranged so as to sandwichthe signal lines SL(p−5), SL(p−4) therebetween are connected to eachother by the eleventh switch kp−1, and the signal lines SL(p−4), SL(p−2)arranged so as to sandwich the signal lines SL(p−3), SL(p−2)therebetween are connected to each other by the eleventh switch kp.

In the third embodiment, further, the signal line for magnetic fieldSL(dL) and the signal line SL(2) arranged so as to sandwich the signallines SL(0), SL(1) therebetween are connected to each other by the tenthswitch j00, and the signal line for magnetic field SL(dR) and the signalline SL(p−2) arranged so as to sandwich the signal lines SL(p−1), SL(p)therebetween are connected to each other by the tenth switch j01.

Accordingly, as described with reference to FIGS. 16 to 18, coils havingthe signal lines SL(0) to SL(p) as winding wires can be formed in themagnetic field detection period TDT. Further in the third embodiment,coils can be formed also in vicinity of the sides 2-R. 2-L of thedisplay panel 2 in the magnetic field detection period TDT. That is, acoil having the signal lines SL(0), SL(1) arranged close to the side 2-Lof the display panel 2 inside can be formed of the signal line formagnetic field SL(dL) and the signal line SL(2). Similarly, a coilhaving the signal lines SL(p−1), SL(p) arranged close to the side 2-R ofthe display panel 2 inside can be formed of the signal line for magneticfield SL(dR) and the signal line SL(p−2). Accordingly, the pen PN can bedetected even if the pen PN approaches the side 2-R or the side 2-L.Also in the third embodiment, as similar to the coils described withreference to FIGS. 16 to 18, the formed coils overlap with each other.Accordingly, detection missing can be prevented.

Widths d8, d10 of the signal lines for magnetic field SL(dR), SL(dL) aremade narrower than widths d9, d10 of the signal lines SL(0) to SL(p).Accordingly, increase in a size of a frame can be prevented.

In the magnetic field detection period TDT, the ground voltage Vss issupplied to one terminal of a pair of terminals of each of coils formedof signal lines, and the other terminal thereof is connected to theinput terminal XIO of the selection control circuit SRX-D via the fourthswitch described with reference to FIG. 16. In the description of FIG.29 as an example, an end of the signal line SL(n−2) is connected to theinput terminal XIO(n−1) via the fourth switch d00 shown in FIG. 16, anend of the signal line SL(n) is connected to the input terminal XIO(n)via the fourth switch d01 shown in FIG. 16, and an end of the signalline SL(n+2) is connected to the input terminal XIO(n+1) via the fourthswitch d02 shown in FIG. 16.

In the magnetic field detection period TDT, by turning on the fourthswitch (for example, the fourth switch d01) by the selection signalsX-Out(0) to X-Out(p) from the selection control circuit SRX-D, a signaldepending on whether or not an induced voltage is generated in the coilformed of the signal lines SL(n), SL(n+3) by a magnetic field generatedfrom the pen PN is transferred to the input terminal XIO(n) and isoutput as a sense signal.

In FIG. 29, note that drive electrodes and signal lines are separatelyshown for the description. However, drive electrodes and signal linesoverlap in an electrically-insulated state.

The third embodiment describes an example in which the signal lines formagnetic field SL(dR), SL(dL) to be winding wires for forming a coil areprovided along both sides of the display panel 2. However, of course,the signal lines for magnetic field may be provided along either oneside. The tenth switch j00 and the eleventh switches k00 to kp may beturned on after a predetermined time passes from the change of themagnetic-field enable signal SC_EN to the high level. In this manner,the tenth switches and the eleventh switches may be turned on in themagnetic field detection period TDT even in touch detection.

FIG. 33 is a schematic diagram schematically showing an outline of theliquid crystal display apparatus 1 according to the third embodiment.This drawing shows the drive electrodes TL(0) to TL(p), the signal linesSL(0) to SL(p), the eleventh switches k00 to kp, the semiconductordevice for drive DDIC, twelfth switches l00 to lp, the selection controlcircuits SR1-R, SR1-L, the switching circuit DSC, and the selectiondrive circuit SDC. They are formed on a TFT glass substrate. Thus, theliquid crystal display apparatus 1 mounted on a module can be consideredto be shown in FIG. 33. In FIG. 33, the pen PN including the coil L1 isalso shown.

The switching circuit DSC and the selection control circuit SR1-R arearranged along the side 500-R of the module, and the selection drivecircuit SDC and the selection control circuit SR1-L are arranged alongthe side 500-L. The signal lines SL(0)˜SL(p) are arranged between theswitching circuit DSC and the selection drive circuit SDC so as to beparallel to each other, the eleventh switches k00 to kp are arrangedalong the side 500-U of the module, and the twelfth switches l00 to lpare arranged along the side 500-D. The drive electrodes TL(0) to TL(p)are arranged between the eleventh switches k00 to kp and the twelfthswitches l00 to lp so as to be parallel to each other.

As described with reference to FIG. 29, the eleventh switches k00 to kpconnect signal lines in touch detection.

The twelfth switches l00 to lp are categorized into two groups, and thetwelfth switches in the first group are connected between a voltage wireVL3 and an end of each of signal lines such as the signal lines SL(2),SL(n+3), SL(p−1) shown in FIG. 29 to which the ground voltage Vss shouldbe supplied in the magnetic field detection period TDT, and are turnedon in the magnetic field detection period TDT. The twelfth switches inthe second group are connected between a corresponding signal wire LL7and an end of each of signal lines such as the signal lines SL(1),SL(n), SL(p−4) shown in FIG. 29 from which a signal change in a coil isoutput in the magnetic field detection period TDT. As exemplification inFIG. 33, references characters l00, ln, ln+3, lp are attached to thetwelfth switch (of the second group) connected to an end of the signalline SL(0), the twelfth switch (of the second group) connected to an endof the signal line SL(n), the twelfth switch (of the first group)connected to an end of the signal line SL(n+3), and the twelfth switch(of the first group) connected to an end of the signal line L(p),respectively. Although the signal wire LL7 is shown as a wire, thesignal wire includes signal wires as many as the number corresponding tothe twelfth switches of the second group. The twelfth switches of thesecond group are also turned on in a magnetic field detection period.Accordingly, a signal generated in each coil is transferred to thecorresponding signal wire LL7, is amplified by an amplifier circuit AMP,and is supplied to the semiconductor device for touch detection 6 (FIG.6) as the sense signals S(0) to S(p).

In the third embodiment, the twelfth switches l00 to lp are formed on aTFT glass substrate, and the semiconductor device for drive DDIC isarranged so as to cover the twelfth switches l00 to lp. Accordingly,widening of the frame can be suppressed.

In the touch detection, three coils having the drive electrodes TL(n−1)to TL(n+1), TL(n+3) to TL(n+5) as winding wires are formed by theselection control circuits SR1-R, SR1-L, the switching circuit DSC, andthe selection drive circuit SDC, and a magnetic-field drive signal issupplied to each of the three coils. Accordingly, a drive current asindicated by a solid line I with an attached arrow in FIG. 33 flows. Amagnetic field is generated in each of the three coils by periodicchanges of the magnetic-field drive signal. FIG. 33 schematically showsan appearance of a generated magnetic field □G by a broken line. Notethat the direction of arrow has no particular meaning, and shows that astrong magnetic field is generated from an area (drive electrodeTL(n+2)) where the three coils overlap.

If the pen PN exists in vicinity of an area where the three coilsoverlap with one another, an induced voltage is generated in the coil L1inside the pen PN by the action of mutual induction. The capacitativeelement C (not shown) inside the pen PN is charged by the generatedinduced voltage.

In the magnetic field detection period TDT, the coil L1 inside the penPN generates a magnetic field by charges charged in the capacitativeelement C. The line of magnetic force at this time is shown as □D inFIG. 33.

As described with reference to FIG. 29, in the magnetic field detectionperiod TDT, the eleventh switches k00 to kp are turned on. Accordingly,a plurality of coils having the signal lines SL(0) to SL(p) as windingwires are formed. By the action of mutual induction between a coilhaving signal lines as winding wires and the coil L1 inside the pen PN,an induced voltage is generated in the coil having signal lines aswinding wires, so that a signal in the signal lines is transferred tothe twelfth switches of the second group. The signal is output from theamplifier circuit AMP as the sense signals S(0) to S(p) by turning onthe twelfth switches of the second group. In FIG. 33, the signaltransferred to the twelfth switch ln via the signal line SL(n) is shownby a solid line with an attached arrow.

An example in which the signal lines for magnetic field SL(dL), SL(dR)are arranged outside the active area of the display panel 2 has beendescribed. However, the present embodiment is not limited to such anexample. For example, along the side 2-L or the side 2-R inside theactive area of the display panel 2, the signal line for magnetic fieldSL(dL) and/or the signal line for magnetic field SL(dR) may be arranged.In such a case, by making the width d10 of the signal line for magneticfield SL(dL) and/or SL(dR) to be arranged narrower than the width d11 ofsignal lines, narrowing of the display area can be reduced.

Fourth Embodiment

FIG. 30 is a timing chart showing the operation of the liquid crystaldisplay apparatus 1 according to the fourth embodiment. Here, while theliquid crystal display apparatus 1 according to the first embodimentwill be described as an example, the same goes for the second embodimentand the third embodiment.

In FIG. 30, the horizontal axis represents the time. FIG. 30A shows aframe signal F that is periodically generated, and the liquid crystaldisplay apparatus displays, for example, an image corresponding to onescreen in one frame period Tf defined by the frame signal F. In thefourth embodiment, the control circuit D-CNT shown in FIG. 6 performscontrol so that a plurality of display periods and a plurality of touchdetection periods are alternately generated in one frame period Tf.FIGS. 30B to 30G show the timing in one frame period Tf of a pluralityof frame periods Tf. That is, the timing shown in FIGS. 30B to 30Goccurs in each of the plurality of frame periods Tf.

Here, FIG. 30B schematically shows display periods and touch detectionperiods generated in one frame period Tf. FIG. 30C shows a waveform ofthe selection signals SEL1, SEL2 supplied to the signal line selector 3(FIG. 6). FIG. 30D shows a waveform of the magnetic-field enable signalSC_EN. FIGS. 30E and 30F show waveforms of the selection signals Ty(n)R,Ty(n)L and the selection signals Ty(n+2)R, Ty(n+2)L of selection signalsfrom the selection control circuits SR-R, SR-L. FIG. 30G shows signalchanges in coils formed by using drive electrodes and coils formed byusing signal lines.

As shown in FIG. 30B, the control circuit D-CNT performs control so thatthe display period DISP1 (DISP2) and the touch detection period SEN1(SEN2) are alternately generated in time series in each frame period Tf.That is, in the display period DISP1 (DISP2), an image signal Sn is setto be supplied to the appropriate signal line by supplying the imagesignal Sn from the signal driver D-DRV (FIG. 6) to the signal lineselector 3 so that the selection signals SEL1, SEL2 are alternately setto the high level. In FIG. 30C, note that the selection signals SEL1,SEL2 are shown as one waveform in order to show that the selectionsignals SEL1, SEL2 change. Also in the display period DISP1 (DISP2), theswitching circuit DSC and the selection drive circuit SDC are controlledby the selection control circuits SR-R, SR-L so that a display drivesignal is supplied from the switching circuit DSC and the selectiondrive circuit SDC to the drive electrodes TL(0) to TL(p). Further, thegate driver 5 (FIG. 6) is controlled so that an appropriate scanningsignal is supplied from the gate driver 5 to the scanning lines GL(0) toGL(P). Accordingly, in the display period DISP1 (DISP2), the displaypanel 2 performs the display in accordance with the image signal Sn.

As shown in FIG. 30D, in the touch detection period SEN1 (SEN2), thecontrol circuit D-CNT sets the magnetic-field enable signal SC_EN to thehigh level. Accordingly, the selection control circuits SR-R, SR-L sets,for example, the selection signals Ty(0)R, Ty(0)L to Ty(p)R, Ty(p)L tothe high level in this order. FIG. 30 shows a state in which theselection signals Ty(n)R, Ty(n)L change to the high level in the touchdetection period SEN1 and in which the selection signals Ty(n+2)R,Ty(n+2)L change to the high level in the next touch detection periodSEN2.

The touch detection period SEN1 (SEN2) includes the magnetic fieldgeneration period TGT in which a magnetic field is generated and themagnetic field detection period TDT subsequent to the magnetic fieldgeneration period TGT. In the magnetic field generation period TGT, acoil is formed by using drive electrodes, and a magnetic field isgenerated by the formed coil. An induced voltage is generated in thecoil L1 by mutual induction between the coil and the coil L1 inside apen (FIGS. 1 and 2), so that the capacitative element C inside the pen(FIG. 2) is charged. In the magnetic field detection period TDT, thecoil L1 inside the pen generates a magnetic field in accordance with theamount of charge charged in the capacitative element C. Also in themagnetic field detection period TDT, a coil is formed by using signallines. An induced voltage is generated in the coil formed of signallines by mutual induction between the coil formed of signal lines andthe coil L1 inside the pen. The pen is detected by detecting a flowingcurrent of the signal lines caused by the induced voltage.

In the magnetic field generation period TGT, the control circuit D-CNTsupplies the coil clock signal CCLK to the signal wire LL3. In themagnetic field detection period TDT, the control circuit D-CNT stops thesupply of the coil clock signal CCLK, performs control so that anexternal terminal of the semiconductor device for drive DDIC connectedto the terminal SP (FIG. 16) is in a high-impedance state, and so thatthe signal line selector 3 (FIG. 16) connects the terminal SP and signallines by the selection signals SEL1, SEL2. Accordingly, when a coil isformed by using the signal lines SL(0) to SL(p), the coil is put into ahigh-impedance state.

By the state in which the selection signals Ty(n)R, Ty(n)L are changedto the high level, as described in the first embodiment, two coilshaving drive electrodes as winding wires are formed. Areas of the twoformed coils overlap in the drive electrodes TL(n), TL(n+1)corresponding to the selection signals TY(n)R, Ty(n)L. In the magneticfield generation period TGT, the signal wire LL3 is connected to each ofthe two coils, and the coil clock signal CCLK is supplied to each coilas a magnetic-field drive signal. As a result, a magnetic field changingin accordance with the magnetic-field drive signal is generated in eachof the two coils, and magnetic fields are superimposed in an areacorresponding to the drive electrodes TL(n), TL(n+1) to generate astrong magnetic field (“Occurrence of magnetic field in drive electrodecoil” is described in FIG. 30).

In the magnetic field detection period TDT, as described in the firstembodiment, a plurality of coils CX(0) to CX(p) (see FIG. 18) are formedof the signal wires SL(0) to SL(p). In the touch detection period SEN1,the amount of charge charged in the capacitative element C inside thepen changes depending on whether or not a pen approaches an areacorresponding to the drive electrode TL(n) in the magnetic fieldgeneration period TGT. In the magnetic field detection period TDT,coordinates or others of an area to which the pen approaches can bedetermined by detecting a current in each of the plurality of coilsCX(0) to CX(p) (signal-line coil current detection).

Next, the control circuit D-CNT sets the magnetic-field enable signalSC_EN to the low level to perform a display operation in the displayperiod DISP2. After the display period DISP2, the control circuit D-CNTsets the magnetic-field enable signal SC_EN to the high level again.

In synchronization with the change of the magnetic-field enable signalSC_EN to the high level, the selection control circuits SR-R, SR-Lchange the selection signals Ty(n+2)R, Ty(n+2)L to the high level, andmaintain the selection signals Ty(n)R, Ty(n)L at the low level. In thetouch detection period SEN2, the control circuit D-CNT supplies the coilclock signal CCLK to the signal wire LL3 in the magnetic fieldgeneration period TGT, and stops the supply of the coil clock signalCCLK in the magnetic field detection period TDT. Accordingly, asdescribed in the first embodiment, in the magnetic field generationperiod TGT, two coils overlapping with each other in an areacorresponding to the drive electrode TL(n+1) are formed so that a strongmagnetic field is generated in an area corresponding to the driveelectrodes TL(n+2), TL(n+3), a magnetic field in accordance with changesof the coil clock signal CCLK (magnetic-field drive signal) is generatedby each coil, and the magnetic fields are superimposed in the areacorresponding to the drive electrodes TL(n+2), TL(n+3).

In the magnetic field detection period TDT, the coils CX(0) to CX(p) areformed of signal lines, and coordinates or others of an area to which apen approaches are determined by detecting a current from each coil.

By repeating the operation in the touch detection period describedabove, a strong magnetic field is successively generated from the side2-U toward the side 2-D of the display panel 2 for, for example, eacharea corresponding to two drive electrodes as a unit. The position towhich a pen approaches in an area where a strong magnetic field isgenerated is determined by currents from the coils CX(0) to CX(p).Accordingly, for example, the touch on the entire surface of the displaypanel 2 can be detected in one frame period Tf.

In the magnetic field generation period TGT, the selection drive circuitSDC connects drive electrodes corresponding to the high-level selectionsignal to the signal wire LL3 and the voltage wire VL2, and puts driveelectrodes corresponding to low-level selection signals into a floatingstate. As described as an example, when the selection signal Ty(n)L isat the high level, the drive electrodes TL(n−2), TL(n−1) are connectedto the signal wire LL3, and the drive electrodes TL(n+2), TL(n+3) areconnected to the voltage wire VL2. Drive electrodes except for thesefour drive electrodes, that is, the drive electrodes TL(0) to TL(n−3),TL(n), TL(n+1), and TL(n+4) to TL(p) are put into a floating state. Inother words, these drive electrodes TL(0) to TL(n−3), TL(n), TL(n+1),and TL(n+4) to TL(p) are in a high-impedance state.

Also in the fourth embodiment, a high-impedance control signal HZ-CT issupplied from the control circuit D-CNT to the gate driver 5 and thesignal line drive circuit D-DRV. In the magnetic field generation periodTGT, the control circuit D-CNT performs control so that the output ofeach of the gate driver 5 and the signal line drive circuit D-DRV is putinto a high-impedance state by the high-impedance control signal HZ-CT.Accordingly, in the magnetic field generation period TGT, the signallines SL(0) to SL(p) and the scanning lines GL(0) to GL(p) are floatedand are put into a high-impedance state. As a result, all of driveelectrodes, signal lines, and scanning lines that do not form a coil areput into a high-impedance state. Accordingly, when coils are driven bythe coil clock signal CCLK, the parasitic capacitance to be charged canbe reduced, so that the magnetic field generation period can beshortened, and the accuracy of magnetic field detection can be improved.

Fifth Embodiment

In the first to fourth embodiments, the coil that generates magneticfields in the magnetic field generation period TGT and the coil thatdetects a magnetic field in the magnetic field detection period TDT aredifferent from each other. That is, in the magnetic field generationperiod TGT, a magnetic field is generated by coils formed by using driveelectrodes arranged in parallel with the row direction of the displaypanel 2 (pixel array LCD). On the other hand, in the magnetic fielddetection period TDT, a magnetic field is detected by coils formed byusing signal lines arranged in parallel with the column direction of thedisplay panel 2 (pixel array LCD). By contrast, in the fifth embodiment,a magnetic field is generated by using coils formed of drive electrodesin the magnetic field generation period TGT, and a magnetic field isdetected by using coils formed of drive electrodes in the magnetic fielddetection period TDT. That is, coils formed by using drive electrodesare used for both of magnetic field generation and magnetic fielddetection. In this case, by using the coils formed by using signal linesfor both of magnetic field generation and magnetic field detection,coordinates of an area to which a pen approaches can be extracted.

Here, a case when coils formed by using drive electrodes are used forboth of magnetic field generation and magnetic field detection will bedescribed.

FIG. 31 is a circuit diagram showing an example of a magnetic fielddetection circuit used for the liquid crystal display apparatus 1according to the fifth embodiment. In FIG. 31, reference charactersCY(0) to CY(p) indicate coils formed in a touch detection period. areference character SWCT indicates a switch unit having a plurality ofswitches SWRL switch-controlled by a switch control signal SWC. Here,for example, the switch SWRL corresponds to the second switches b00 tob09 shown in FIG. 11, and the switch control signal SWC corresponds tothe selection signals Ty(n−2)L to Ty(n+6)L.

In a touch detection period, one end of each of the coils CY(0) to CY(p)is connected to the ground voltage Vss, and the other end thereof isconnected to a node n4 via the corresponding switch SWRL and signal wireLL3. A detection signal in the node n4 is supplied to a gain circuit andis amplified by the gain circuit. The amplified detection signal issupplied to a filter circuit in order to remove noise, and the output ofthe filter circuit is rectified by a rectification circuit and issupplied to an integrating circuit. The output of the integratingcircuit is supplied to a micro-controller MCU.

Although not shown, the micro-controller MCU includes an analog/digitalconversion circuit, a clock signal generator circuit, a nonvolatilememory storing a program, and a processing unit operating in accordancewith the program stored in the nonvolatile memory. The output from theabove-described integrating circuit is supplied to the analog/digitalconversion circuit via a terminal ADC of the micro-controller MCU and isconverted into a digital signal. The digital signal obtained by theconversion is processed by the processing unit to determine whether ornot a pen approaches any of the coils CY(0) to CY(p).

The processing unit in the micro-controller MCU forms a control signalin accordance with a program. The control signal includes the switchcontrol signal SWC, an enable signal EN, and a reset signal rst. Also,the clock signal CLK whose voltage changes periodically is generated bythe clock signal generator circuit in the micro-controller MCU. Theclock signal is used as the coil clock signal CCLK.

The coil clock signal CCLK is supplied to a buffer circuit BF. Thebuffer circuit BF is controlled by the enable signal EN. When the enablesignal EN is at the high level, the coil clock signal CCLK is suppliedto the node n4 via a resistor R11. On the other hand, when the enablesignal EN is at the low level, the output of the buffer circuit BF is ina high-impedance state (Hi-Z).

The gain circuit includes resistors R8 to R10, an operational amplifierOP4, and a capacitative element CP3 for DC cutting. A detection signalis supplied to a positive-phase input (+) of the operational amplifierOP4, and an inverse input (−) of the operational amplifier OP4 isconnected to the ground voltage Vs via the resistor R9 and is alsoconnected to the output of the operational amplifier OP4 via theresistor R8.

The filter circuit includes resistors R4 to R7, a capacitative elementCP2, and an operational amplifier OP3. The positive-phase input (+) ofthe operational amplifier OP3 is connected to the ground voltage Vs viathe resistor R7, and an output signal from the gain circuit is suppliedthereto via the capacitative element CP2. The inverse input (−) of theoperational amplifier OP3 is connected to the ground voltage Vs via theresistor R6, and further connected to the output of an operationalamplifier via the resistor R5. Further, the output of the operationalamplifier OP3 is connected to the input of the filter circuit via theresistor R4.

The rectification circuit includes resistors R1 to R3, an operationalamplifier OP2, and a diode D. The positive-phase input (+) of theoperational amplifier is connected to the ground voltage Vs via theresistor R3, and the output from the filter circuit is supplied to theinverse input (−) of the operational amplifier OP2 via the resistor R2.Further, the output of the rectification circuit is supplied thereto viathe resistor R1. The output of the operational amplifier OP2 is outputvia the diode D.

The integrating circuit includes a capacitative element CP1, a switchSW13 that receives the reset signal rst as a switch control signal, andan operational amplifier OP1. The positive-phase input (+) of theoperational amplifier is connected to the ground voltage Vs, and theinverse input (−) thereof is connected to the output of the integratingcircuit via the capacitative element CP1. The switch SW13 is connectedbetween the output and the input of the integrating circuit.

FIG. 32 is a waveform chart showing the operation of the magnetic fielddetection circuit shown in FIG. 31. In FIG. 32, the horizontal axisrepresents the time, and the vertical axis represents the voltage. FIG.32A shows the waveform of the coil clock signal CCLK, FIG. 32B shows thewaveform of the switch control signal SWC, and FIG. 32C shows thewaveform of the enable signal EN. Also, FIG. 32D shows the waveform ofthe reset signal rst, FIG. 32E shows an output waveform OUT1 of the gaincircuit, and FIG. 32F shows the waveform of an output OUT2 of theintegrating circuit. Note that the operation of touch detection is shownin FIG. 32 and that the operation of a display period is omitted.

First, a reset is canceled by a state in which the reset signal rst isset to the low level at time t0. At this time, the micro-controller MCUsets the enable signal EN to the high level. Accordingly, the coil clocksignal CCLK is supplied from the buffer circuit BF to the node n4 viathe resistor R11. At this time, the micro-controller MCU outputs such aswitch control signal SWC as turning on the switch SWRL correspondingto, for example, the coils CY(n−2), CY(n−1). Here, the correspondencebetween the ON state/OFF state of the switch SWRL and the second switchshown in FIG. 11 will be described as follows. That is, in the examplewith the second switches b00, b01, b04, b05 shown in FIG. 11, the ONstate of the switch SWRL means a state in which the common terminal c ineach of the second switches b00, b01 is connected to the second terminalp2 and in which the common terminal c in each of the second switchesb04, b05 is connected to the third terminal p3. On the other hand, theOFF state of the switch SWRL means a state in which the common terminalc in each of the second switches b00, b01, b04, b05 is connected to thefourth terminal.

By the ON state of the switches SWRL (the second switches b00, b01, b04,b05 in FIG. 11) corresponding to the coils CY(n−2), CY(n−1), the coilclock signal CCLK supplied to the node n4 is supplied to an end of eachof the coils CY(n−2), CY(n−1) as a magnetic-field drive signal.

The coil clock signal CCLK supplied to the node n4 is also supplied tothe gain circuit. An output OUT1 of the gain circuit changes inaccordance with voltage changes of the coil clock signal CCLK, and thus,changes as shown in FIG. 32E. The output OUT1 of the amplifier circuitis supplied to the rectification circuit via the filter circuit, and therectified output is supplied to the integrating circuit. While thevoltage of the node n4 changes periodically from time t0 to time t1,there is no change in terms of an envelope curve, and thus, the outputof the integrating circuit is a fixed value.

At time t1, the micro-controller MCU sets the enable signal EN to thelow level. Accordingly, the node n4 is put into a high-impedance state(Hi-Z). Also at time t1, the micro-controller MCU forms such a switchcontrol signal SWC as maintaining the ON state of the switches SWRL(b00, b01, b04, b05) corresponding to the coils CY(n−2), CY(n−1) and asturning off the rest of SWRL (b02, b03, b06 to b09). Accordingly, an endof each of the coils CY(n−2), CY(n−1) is maintained in a connected stateto the node n4, and other coils are maintained in a disconnected statefrom the node n4. Between time t0 and time t2 in the example of FIG. 32,the pen does not approach an area where the coils CY(n−2), CY(n−1)overlap, and thus, no magnetic energy is provided from the pen to thecoils CY(n−2), CY(n−1). Therefore, the output OUT2 of the integratingcircuit does not change.

Before shift to time t2, the micro-controller MCU temporarily sets thereset signal rst to the high level and also sets all the switch controlsignals SWC to the low level. Accordingly, the reset is set, and then,the reset is canceled by setting the reset signal rst to the low levelagain. The interval between time t2 and time t3 is the same in thesignals as the interval between time t0 and time t1.

At time t3, the micro-controller MCU forms such a switch control signalSWC as maintaining the ON state of the switches SWRL (b02, b03, b06,b07) corresponding to the coils CY(n), CY(n+1) and as turning off theswitches SWRL corresponding to the rest of switches. Note that FIG. 32Bshows the waveform of the switch control signal SWC supplied to theswitch SWRL corresponding to the coils CY(n−2), CY(n−1) between time t0and time t2, and shows the waveform of the switch control signal SWCsupplied to the switch SWRL corresponding to the coils CY(n), CY(n+1)between time t2 and time t4.

At time t3, the micro-controller MCU sets the enable signal EN to thelow level. Accordingly, the node n4 is put into the high-impedancestate. At this time, a pen exists in vicinity of an area where the coilsCY(n), CY(n+1) overlap, and thus, an induced voltage is generated in thecoils CY(n), CY(n+1) by a magnetic field generated in an area where thecoils CY(n), CY(n+1) overlap between time t2 and time t3, so that thecapacitative element C (FIG. 2) is charged.

At time t3, the coil L1 inside the pen generates a magnetic field basedon the amount of charge charged in the capacitative element C. Aninduced voltage is generated in the coils CY(n), CY(n+1) by changes ofthe magnetic field generated by the coil L1.

As a result, as shown in FIG. 32E, the output OUT1 of the gain circuitattenuates while oscillating. That is, the voltage attenuates in termsof an envelope curve. The output OUT1 of the gain circuit attenuatesfrom time t3 while oscillating, and thus, the output OUT2 of theintegrating circuit gradually increases. The micro-controller MCUdetermines that a pen exists based on a result of conversion of theoutput OUT2 of the integrating circuit into a digital signal. At thistime, the micro-controller MCU can get the position of the selected coilof the coils CY(0) to CY(p) by setting the switch control signal SWC tothe high level, and thus, can determine the position where the penexists, that is, the position at which the pen touches, and a penpressure of the pen or others from the value of the digital signalobtained by conversion and the getting coil position.

By repeating the above-described operation, it can be determined whetherthe pen exists or not, and the pen pressure of the pen or others can bedetermined. The explanation has been made while exemplifying the coilsCY(0) to CY(p), and a similar operation can also be performed to thecoils CX(0) to CX(p). Each of the coils CX(0) to CX(p) at this time isformed of, for example, signal lines. In FIG. 15, an example of thecoils CX(n) to CX(n+5) formed of the signal lines SL(n−2) to SL(n+7) isshown as a plan view. Also, by performing the magnetic field generationand the magnetic field detection described with reference to FIGS. 31and 32 for each of the coils CY(0) to CY(p) and the coils CX(0) toCX(p), coordinates of an area which the pen approaches can be extracted.

In the fifth embodiment, the resistor R9 of the gain circuit may beconnected to the ground voltage Vs via a switch switch-controlled by thereset signal rst. In this manner, power consumption can be reduced. Theresistor R11 is provided to limit the current generated when the clocksignal CLK is supplied. Thus, the resistor R11 may not be provided whenthe resistance of the coil is relatively high.

In a plurality of the embodiments described above, drive electrodes towhich a display drive signal is supplied is formed of a plurality of thedrive electrodes TL(0) to TL(p) in the display period. In the touchdetection, these drive electrodes are used as winding wires to formcoils. In addition, during the display period, a coil is formed by usingthe signal lines SL(0) to SL(P) used for transferring an image signal inthe touch detection. Here, as shown in FIG. 9, the signal lines SL(0) toSL(p) are formed of wires formed in the second wiring layer 603 lowerthan the third wiring layer 605 forming the drive electrodes TL(0) toTL(p). Thus, if the drive electrode is formed of one electrode, an eddycurrent is generated in the drive electrode by a magnetic fieldgenerated by the coil L1 inside the pen in the magnetic field detectionperiod TDT. Therefore, the magnetic field generated by the coil L1inside the pen is consumed by the generation of the eddy current, andthe magnetic field reaching the coil formed of signal lines isconsidered to be weakened.

On the other hand, if the drive electrode is formed of a plurality ofdrive electrodes, an area where an eddy current is generated can benarrowed, so that weakening of the magnetic field due to the driveelectrode can be reduced. If the drive electrode is formed of theplurality of drive electrodes, the impedance of each drive electrodeincreases. However, as described in the embodiments, the impedance ofthe drive electrode (including an auxiliary electrode) caused when acoil is formed can be decreased by connecting the auxiliary electrode tothe drive electrode to use the auxiliary electrode also as a wire of thecoil. Further in the embodiment, the impedance is decreased bydecreasing the number of windings of a coil to shorten the length of thecoil. In addition, the generated magnetic field is made stronger bymagnetic fields being superimposed in an area where a plurality of coilsoverlap.

In the plurality of embodiments described above, a single-winding coilhas been described as an example of the coil that generates a magneticfield. However, the winding is not limited to such an example. Forexample, each of a plurality of coils that generate a magnetic fieldsubstantially at the same time may be a 1.5-winding or 2 or more-windingcoil.

The numbers of signal wires and voltage wires described with referenceto FIGS. 11, 23, and 24 are not limited. For example, these signal wiresor voltage wires may also serve as other signal wires or voltage wires.

The embodiments have been described an example in which the selectioncontrol circuits SR-R, SR-L, SR1-R, SR1-L, the switching circuit DSC,and the selection drive circuit SDC are provided on a TFT glasssubstrate. However, they may not be provided on a TFT glass substrate.For example, these circuits or some of these circuits may be provided inthe flexible cables FB1, FB2 shown in FIG. 7. However, by providingthese circuits on a TFT glass substrate, the increase in the number ofterminals can be suppressed.

Further, the embodiments have described an example of forming aplurality of coils by using drive electrodes arranged close to eachother. However, the formation is not limited to such an example. Forexample, a plurality of coils may be formed by using a plurality ofdrive electrodes that are separated from each other. In such a case, ifareas of the formed coils overlap, magnetic fields are superimposed inan overlapped area, and thus, a strong magnetic field can be generated.

Examples generating a magnetic field by a coil having a drive electrodeor a signal line as a winding wire have been described. Of course, thewinding wire of a coil that generates a magnetic field is not limited tothe drive electrode or the signal line, and may be a signal wire such asa scanning line.

Examples of generating a strong magnetic field in an area where aplurality of coils overlap by supplying a magnetic-field drive signal tothese coils substantially at the same time have been described.Similarly, a plurality of coils can be also used as coils to detect amagnetic field. However, for improving the accuracy of detection, it ismore effective to generate a strong magnetic field to increase theamount of charge charged in the pen PN.

In the embodiments, the detection of the touch of the pen by using theelectromagnetic induction system has been described. For example, fordetecting the touch of a finger, usage of the capacitance system, whichis different from the electromagnetic induction system, is known. Atouch detection function of the capacitance system may be added to theconfiguration described in the embodiments. In this case, for example, adetection electrode is arranged so as to be perpendicular to the driveelectrode, and an electric field drive signal is supplied to the driveelectrode when the touch of a finger is detected. A signal in thedetection electrode changes depending on whether a finger touches ornot. Therefore, by detecting such a change, the touch of a finger can bedetected. In this case, a display drive signal, a magnetic-field drivesignal, or an electric field drive signal is supplied to the driveelectrode.

In the scope of the idea of the present invention, various modifiedexamples and alteration examples could have been easily thought up bythose who skilled in the art, and it would be understood that thesevarious modified examples and alteration examples belong to the scope ofthe present invention.

For example, the ones obtained by appropriate addition, removal, ordesign-change of the components to/from/into each of the above-describedembodiments by those who skilled in the art or by addition, omitting, orcondition-change of the step to/from/into each of the above-describedembodiments are also within the scope of the present invention as longas they include the concept of the present invention.

For example, the embodiments have described a case in which the commonelectrodes TL(0) to TL(p) and the signal lines SL(0) to SL(p) extend inthe column direction and are arranged in the row direction. However, therow direction and the column direction change depending on theviewpoint. A case in which the common electrodes TL(0) to TL(p) and thesignal lines SL(0) to SL(p) extend in the row direction and are arrangedin the column direction by the change of the viewpoint is also includedin the scope of the present invention. A term “parallel” used in thepresent specification means extensions from one end to the other endwithout intersecting with each other. Thus, even if one line is inclinedpartially or entirely with respect to the other line, this state is alsoassumed to be “parallel” in the present specification as long as theselines do not intersect with each other from one end to the other end.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The application is claimed as follows:
 1. A display apparatuscomprising: a pixel array having a plurality of pixels including aplurality of pixel electrodes and a plurality of common electrodes togenerate an electromagnetic field for displaying an image; a pluralityof signal lines arranged in a first direction and extending in a seconddirection crossing the first direction to supply an image signal to aplurality of pixels for displaying the image; and a first switchingcircuit coupled to the plurality of signal lines including a firstsignal line and a second signal line, wherein the first switchingcircuit electrically connects between a first port of the first signalline and a first port of the second signal line to form a coil with thefirst single line and the second line for touch detection.
 2. Thedisplay apparatus according to claim 1, further comprising: a secondswitching circuit coupled to the plurality of signal lines, wherein theplurality of signal lines further includes a third signal lineadjacently arranged to the first signal line and a fourth signal lineadjacently arranged to the second signal line, and wherein the firstswitching circuit electrically connects between a first port of thethird signal line and a first port of the fourth signal line, and thesecond switching circuit connects between a second port of the secondsignal line and a second port of the third signal line to detect theexternally-approaching object.
 3. The display apparatus according toclaim 2, wherein at least one signal line, which is floating, isarranged between the second signal line and the third signal line. 4.The display apparatus according to claim 2, further comprising: avoltage wire coupled to the second switching circuit to supply a secondport of the fourth signal line with a first predetermined voltage; and adriving circuit coupled to the second switching circuit to supply asecond port of the first signal line with a first driving signal.
 5. Thedisplay apparatus according to claim 4, wherein the first predeterminedvoltage is a constant voltage, and the first driving signal is an ACvoltage.
 6. A display apparatus comprising: a pixel array having aplurality of pixels including a plurality of pixel electrodes and aplurality of common electrodes to generate an electromagnetic field fordisplay; a plurality of signal lines arranged in a first direction andextending in a second direction crossing the first direction to supplyan image signal to a plurality of pixels; and a first switching circuitcoupled to the plurality of common electrodes, wherein the plurality ofcommon electrodes include a first common electrode and a second commonelectrode arranged in the second direction and extending in the firstdirection to supply a drive signal for touch detection, and wherein thefirst switching circuit electrically connects between a first end of thefirst common electrode and a first end of the second common electrode toform a first coil with the first common electrode and the second commonelectrode for the touch detection.
 7. The display apparatus according toclaim 6, further comprising: a second switching circuit coupled to theplurality of common electrodes, wherein the plurality of commonelectrodes further include a third common electrode adjacently arrangedto the first common electrode and a fourth common electrode adjacentlyarranged to the second common electrode, and wherein the first switchingcircuit electrically connects between a first port of the third commonelectrode and a first port of the fourth common electrode to form asecond coil to detect the externally-approaching object.
 8. The displayapparatus according to claim 7, wherein the first common electrode andthe third common electrode are disposed closer to a peripheral area thanthe second common electrode and the fourth common electrode, and aresistance of the second common electrode and the fourth commonelectrode is smaller than a resistance of the first common electrode andthe third common electrode.
 9. The display apparatus according to claim7, wherein the first common electrode and the third common electrode aredisposed closer to a peripheral area than the second common electrodeand the fourth common electrode, and a width of the second commonelectrode and the fourth common electrode is wider than a width of thefirst common electrode and the third common electrode.
 10. The displayapparatus according to claim 7, further comprising: a voltage wirecoupled to the second switching circuit to supply a second end of thesecond common electrode and a second end of the fourth common electrodewith a first predetermined voltage; and a signal wire coupled to thesecond switching circuit to supply a second end of the first end of thefirst common electrode and a second end of the third common electrodewith a first driving signal.
 11. The display apparatus according toclaim 9, further comprising: a voltage wire coupled to the secondswitching circuit to supply a second end of the second common electrodeand a second end of the fourth common electrode with a firstpredetermined voltage; and a signal wire coupled to the second switchingcircuit to supply a second end of the first end of the first commonelectrode and a second end of the third common electrode with a firstdriving signal.
 12. The display apparatus according to claim 11, whereinthe first predetermined voltage is a constant voltage, and the firstdriving signal is an AC voltage.
 13. The display apparatus according toclaim 12, wherein a phase of the AC voltage is simultaneously suppliedto the first end of the first common electrode and the second end of thethird common electrode.
 14. The display apparatus according to claim 6,wherein the second direction is along an extending direction of aplurality of gate lines of the pixels.
 15. The display apparatusaccording to claim 14, wherein a total of widths of the commonelectrodes arranged next to each other are substantially the same. 16.The display apparatus according to claim 7, wherein at least one commonelectrode, which is floating, is arranged between the second commonelectrode and the third common electrode.
 17. A display apparatuscomprising: a pixel array having a plurality of pixels including aplurality of pixel electrodes and a plurality of common electrodes togenerate an electromagnetic field for display; a plurality of signallines arranged in a first direction and extending in a second directioncrossing the first direction to supply an image signal to the pluralityof pixels; a plurality of common electrodes arranged in the seconddirection and extending in the first direction to supply a drive signalto the plurality of pixels; a first switching circuit coupled to theplurality of signal lines including a first signal line and a secondsignal line; and a second switching circuit coupled to the plurality ofcommon electrodes including a first common electrode and a second commonelectrode, wherein the first switching circuit electrically connectsbetween the first signal line and the second signal line to form a firstcoil with the first signal line and the second signal line for touchdetection, and the second switching circuit electrically connectsbetween the first common electrode and the second common electrode toform a second coil crossing the first coil with the first commonelectrode and the second common electrode for the touch detection. 18.The display apparatus according to claim 17, wherein a first drivingsignal is applied to the first common electrode and the second commonelectrode, and a second driving signal is applied to the first signalline and the second signal line to detect an externally-approachingobject.
 19. The display apparatus according to claim 17, wherein atleast one signal line, which is floating, is arranged between the secondsignal line and a third signal line.
 20. The display apparatus accordingto claim 17, wherein at least one common electrode, which is floating,is arranged between the second common electrode and a third commonelectrode.